Thompson & Morgan

Important delivery notice
The products on this site are only delivered to UK addresses. If you require delivery to another country please visit one of our other sites below.

Nutritional Guide

What vitamins and minerals are in your vegetables and what are the health benefits?

Common NameScientific NameDescriptionTipsCooking Tips
ManganeseMnManganese is a cofactor of a number of essential enzymes involved in sugar, fat and protein metabolism and is important in reproduction. Perhaps manganese's best known role is as a cofactor of the body's major antioxidant protein, super oxide dismutase (SOD). This has led to its use in many diseases where oxidants are thought to be a contributing factor.Most fruit and vegetables contain moderate amounts of manganese reflecting how important this mineral is to plants as well as humans. Greater amounts can be found in leafy green vegetables. Soils that may suffer from low manganese: alkaline soils high in humus or peaty soils with a pH greater than 6. Plant signs of deficiency include: Yellowing of the leaves (chlorosis), which begins at the top of the plant and works its way down. Veins remain green. Shoots may die back. The amateur gardener can increase the amount of manganese in the soil using organic fertilisers.
Vitamin B2RiboflavinVitamin B2 or riboflavin is needed for growth and the maintenance of healthy skin and eyes. It is an essential factor required for the processing of all major food groups and the release of energy from the diet. Riboflavin is a component of the coenzymes flavin adenine dinucleotide (FAD) and flavin mononucleotde (FMN), which are involved in numerous biochemical reactions.In general, fruit and vegetables are not particularly rich in riboflavin, except for dark green leafy varieties. Since most riboflavin in the diet is derived from animal products, vegetarians must either supplement their diet or eat dark green leafy vegetables on a regular basis, since riboflavin is not stored by the body.Riboflavin is relatively heat stable with losses due to cooking attributed to leaching. Riboflavin is broken down by ultra-violet light.
Essential fatty acids (EFAs)Omega 3 and Omega 6Humans can make most of the fats and oils the body needs for optimum function. However there are two small families of oils, those based on a-linolenic acid (omega 3) and linoleic acid (omega 6) that cannot be made but are essential for human health. Why the body has lost the ability to make these lipids is unclear, but one can assume that at the time of loss they were plentiful in the diet.
Coronary Heart Disease - There is scientific evidence to suggest that a-linolenic acid can decrease the risk of heart attack (myocardial infarction) and sudden cardiac death in individuals with coronary heart disease.
Other Health Benefits - Other studies have shown that fish oil supplements which are rich in a-linolenic acid derivatives decrease joint tenderness and reduce the requirement for anti-inflammatory medication in rheumatoid arthritis patients. A-linolenic acid may be beneficial in the treatment of depression.
A-linolenic acid is present at insufficient evels in the diet of many UK citizens. The richest plant sources are flaxseed, walnuts and their oils - not common additions to most people's diet. The most practical way to add a-linolenic acid to the diet is to eat oily fish twice or more every week - served with a range of home grown vegetables, of course.A-linolenic acid is unstable to heating becoming more unsaturated.
Vitamin B5Pantothenic acidThis vitamin is a component of coenzyme A, an essential factor required for the processing of all major food groups and the production of energy from the diet. Pantothenic acid is a part of coenzyme A, a major element of many biochemical reactions.This vitamin is so important to normal cellular function that it is found in all foods except highly refined commodities such as fat, oil and sugar.Sensitive to heat, acid and alkali. Pantothenic acid is water soluble and tends to leach out into the cooking liquid. Sensitive to thawing.
Vitamin B7BiotinVitamin B7 or biotin is a water-soluble vitamin that is an essential cofactor of carboxylase enzymes and consequently has a role in many of the cells' metabolic pathways. It is essential for cell growth and replication and in particularly the synthesis of fats and sugars. It may also have a role in the metabolism of toxic compounds (detoxification). Biotin is a carrier of one carbon units, often referred to as activated carbon dioxide. The synthesis of many compounds in the cell require the addition of an extra carbon.Plants do not contain large amounts of biotin, however, biotin deficiency is rare as it is synthesised by the gut flora. The best plan is to keep your gut flora happy by eating fermentable fibres such as fructans found in alliums.Biotin is water-soluble and will leach out into cooking liquids.
Vitamin B12CyanocobalamineVitamin B12 is completely absent from plants. Unsurprisingly it is required for the correct function of exclusively animal tissues such as the nervous system and red blood cell formation and so deficiency can lead to nerve damage and anaemia.Liver is a particularly rich source of vitamin B12, but all animal products contain it. Vegetarians need to have foods supplemented with this vitamin.Cyanocobalamine is stable to heating, but being a water-soluble vitamin it tends to leach out into the cooking liquid.
CalciumCaCalcium is the most abundant mineral in the body, making up nearly 40% of the total mineral content, that is most adults contain over 1kg (2.2lbs) of the stuff. This is because it is the major component of bone and teeth (along with phosphorous), which accounts for 99% of its content.
Effects of insufficient calcium - Despite the apparent importance of this role, it is secondary to its physiological functions which include nerve function, muscle contraction and blood clotting. Indeed these latter functions are so important that insufficient calcium in the diet results in it being released from the skeleton. If this occurs for long periods of time the structural strength of the skeleton can be reduced leading to rickets or osteomalacia and osteoporosis, so it's best to ensure you get a regular supply. This may have other benefits for there is some evidence to suggest that calcium may reduce the risk of developing colon cancer and several studies have shown it can lower blood pressure.
Calcium levels in horticultural produce depend on the amount of calcium in the soil. Soils that may suffer from low calcium levels are acid and sandy soils, soils that contain an excess of magnesium or potassium and excessively dry or wet soils. Plant signs of deficiency include: stunted growth; terminal buds become distorted; young leaves turn yellow, starting from the edges, then brown and die. Levels can be increased by the use of lime or bone meal. Fruit and vegetables are not usually regarded as a rich source of calcium, but this is more a reflection of the large amounts required daily by humans rather than low levels in plants.Cooking vegetables in the presence of sodium bicarbonate (alkali) or hard water may reduce the solubility of calcium. Conversely, acid cooking juices may increase solubility - in a similar way vinegar solubilises the limescale that can build up in your kettle.
Flavonoids Flavonoids is the collective name of a diverse group of molecules all based on the flavone backbone. Flavonoids have raised much excitement in the past few years with the increasing evidence that they can have many beneficial effects on human health. They are largely confined to vascular plants, with fruit and vegetables being particularly rich sources. There are six main families: anthocyanidins, flavanols, flavanones, flavonols, flavones and isoflavones.The other major sources of flavonoids besides fruit and vegetables are tea and red wine. Red wine in particular has been associated with a lower rate of cardiovascular disease in France than their fat-rich cuisine would suggest - a phenomenon known as the French paradox. However beware that although red wine may indeed be a good source of flavonids, the alcohol may inhibit the absorption of other nutrients such as many of the B vitamins.
Fibre Fibre is anything in the diet that cannot be digested by the human digestive tract. Scientists tend to group fibre in to classes according to their solubility, viscosity and ability to be digested by gut flora. There is evidence that diets rich in fibre from whole grains, legumes, fruits and non-starchy vegetables can reduce the risk of cardiovascular disease and type 2 diabetes.
Lowering Cholesterol Viscous fibres, such as those found in oat products and legumes, can lower blood cholesterol levels, which may help protect against developing cardiovascular disease. Viscous fibre is thought to decrease the absorption of cholesterol as well as other fats and amino acids from the gut by absorbing water and forming a gel that traps these molecules away from the intestinal lining. An easy way to envisage their action is using the role of pectin in jam making. Pectin is a viscous fibre used to form a gel that suspends the fruit so that it does not sink to the bottom of the jar - the fruit is trapped just like the cholesterol. Viscous fibre also has other effects - it makes you feel full and so (in theory) eat less.
Healthy Bowel High fibre intakes promote bowel health by preventing constipation. Some early scientific studies suggested that people with low fibre intakes had a greater risk of developing bowel cancer, although more recent studies have cast doubt on this conclusion. Fibre compounds that can be fermented (digested by micro organisms) are described as prebiotic since they are food good gut bacterial such as bifidobacteria. Proliferation of these good bacteria causes changes in the environment of the colon preventing the growth of many disease-causing micro-organisms.
We often remove the more fibrous tissues of vegetables before consumption, but leaving these tissues in and maybe chopping them more finely or making a vegetable puree can help increase fibre levels in the diet.
Vitamin B3Niacin & niacinamideNiacin is not regarded by many nutritionists as essential since it can be made by the body from the amino acid tryptophan (a constituent of most proteins), however deficiency can be fatal, underlining its essential role in the body.
Energy Production It is an essential factor required for the processing of all major food groups and the production of energy from the diet. It is necessary for the efficient functioning of the digestive and nervous systems.
Niacin is heat stable, but as a water-soluble vitamin can leach into cooking water.
IronFeAnaemia due to iron deficiency is a well-known condition in the UK, resulting in a low concentration of haemoglobin in the blood. Haemoglobin is the compound that carries oxygen from the lungs to all the other tissues of the body.
Heart Attack Risk Sub-optimal levels of haemoglobin results in the heart having to pump the blood around the body faster in order to supply enough oxygen, which in some cases can increase the risk of heart attack. Iron has many other essential functions in the body and is also involved in processes that may reduce the risk of contracting age-related diseases. This includes its role as an essential cofactor of one of the body's natural antioxidants (catalase and peroxidases) and a family of proteins (cytochrome p450s) involved in the metabolism of many toxic compounds.
Supplement Supervision Essential There are also several serious health consequences to iron overdose, consequently taking iron supplements should be supervised by your doctor. However, like most nutrients the body absorbs more iron from the diet when it is needed, so for most individuals ensuring adequate levels are present in the diet is the best way to ensure sufficiency.
Soils that may suffer from low iron levels: alkaline soils. Excess phosphorus or aluminium. Plant sign of deficiency include: Yellowing of the leaves (chlorosis) begins at the top of the plant and works its way down. Veins remain green. Shoots may die back. The amateur gardener can increase levels by the use of specialist inorganic fertilisers where the iron is present in a chelated form.Iron compounds are stable to heat although some leaching into cooking water can occur.
GermaniumGeThere are some elements that the body may use in such small quantities that deficiency symptoms are never seen and thus science has tended to ignore. Germanium fits into this category with the information of its role in the body based on small amounts of scientific evidence.
Defence against virus-based disease Germanium appears to stimulate the synthesis of interferon, a protein that interferes with the replication of viruses and is produced by the body as a defence against virus-based disease. Germanium appears to inhibit the breakdown of the body's natural painkillers called opiates and in this way prolongs their effects. Germanium may have a role in regulating oxygen supply in the body, unbalances in which many therapists believe are a root cause of illness, consequently germanium supplements have been used in the past to treat a number of illnesses. However, germanium supplements are no longer available due to the inevitable presence of germanium dioxide, a compound with known toxic attributes. Consequently germanium can only be obtained from the diet.
There are no official figures on the germanium content of fruit and vegetables, but garlic, mushrooms, comfrey and ginseng are particularly rich sources. The amateur gardener can use a comfrey fertiliser to increase the levels of germanium (and many other minerals) in their soil. However, it is obviously pointless to grow the comfrey on the site you wish to enrich.
Vitamin CAscorbic acid & Dehydroascorbic acidMost animals can synthesise vitamin C. A notable exception is primates, which appear to have given up this ability 70,000 years ago. Why would a whole order of animals give up the ability to make such an essential compound? In a word – efficiency. Why spend valuable energy making a compound that is readily available in the diet. Unfortunately the diet of many people falls short of the vitamin C content of our ancestors.
Ascorbic acid Ascorbic acid is required for healthy skin, teeth, gums and blood vessels. It assists in the absorption of iron, in healing wounds and broken bones and is necessary for the prevention of scurvy, but its major role in the body is as an powerful water-soluble antioxidant.
Disease & Nerve Damage This antioxidant works together with vitamin A and vitamin E to neutralise oxidants, reactive molecules which can travel through the body causing huge amounts of damage to cells and tissues. Oxidants are a major cause of the build up of cholesterol-filled foam cells in the arterial wall that leads to atherosclerosis and cardiovascular disease, the nerve damage seen in diabetics, cataracts and the joint degeneration seen in osteoarthritis and rheumatoid arthritis. Vitamin C's antioxidant activity also protects essential cell components like DNA from damage by aiding the detoxification of pollutants and other toxins. It is able to inhibit the formation of cancer-causing compounds such as nitrosamines, produced when the body digests processed meats containing nitrates.
Vitamin C is readily excreted from the body in the urine, so ensure that you eat fruit and vegetables rich in vitamin C regularly.Vitamin C is the least stable of all the vitamins, being destroyed by light, heat, air and alkalis. It is also extremely water-soluble and prone to leach into the cooking water.
Anthocyanin Anthocyanins are a family of flavanoids, many of which are responsible for the bright colours of petals, fruits and the bright colours we associate with autumn leaves. Anthocyanin is also produced in leaves that are stressed, giving them a purple tinge and functions in the plant to protect against oxidants, reactive chemicals that can damage cells and tissues.
Antioxidant Properties Their protective effect is derived from their antioxidant potential and this gives us a clue as to how they might protect the human body. Test tube studies using purified anthocyanins or anthocyanin-rich extracts have confirmed the antioxidant potency of these pigments. There is evidence to suggest that the benefits from eating a diet high in anthocyanin may include significant reduction of blood pressure, improvement of eyesight, reduction in the symptoms of inflammatory conditions and a decreased risk of developing some forms of cancer.
Eat a wide range of coloured fruit to maximise the amount of anthocyanin in your diet, including red onions.
PhytoestrogenThere are two distinct classes of phytoestrogens; isoflavones and lignans. They have been shown to exert a wide range of hormonal and other effects in animal studies. Studies suggest that they may lower the risk of contracting many hormone-dependent diseases in women such as cardiovascular disease, osteoporosis, breast cancer and menopausal symptoms. In men they may lower the risk of prostate cancer, as well as cardiovascular disease and osteoporosis. Phytoestrogens may also have antioxidant activity.The richest source of isoflavones is soya, however legumes are also a useful source. Lignans are found in small amounts in many fibre-rich foods.
MagnesiumMgMagnesium is a macromineral being found in large amounts in bone and teeth. It is a cofactor of several hundred enzymes in the human body, many involved in essential metabolism, such as the release and utilisation of energy from food and the metabolism of sugar, fat and proteins.
Preventing Cancer Its role in nucleic acids (RNA & DNA) synthesis and repair may also suggest an important role in preventing cancer. It is required for nerve transmission and muscle contractions including maintaining a regular heart beat rhythm.
Soils that may suffer from low magnesium levels: Wet soils, acid soils, soils high in peat or sand. Also soils given a high concentration of potash, fertilisers or calcium. Plant signs of deficiency include: They first turn yellow, then orange and finally brown. Symptoms first appear on the lower leaves and move up the plant. The amateur gardener can increase the amount of magnesium in the soil by using an organic fertiliser or by applying epsom salts.Magnesium may leach into cooking water. Hard tap water however can contain high amounts of magnesium.
Saponins Saponins are soapy in character and high levels in soapwort have long been known by man as a natural cleanser. It is therefore not surprising that, like soap, saponins interact with cholesterol in the blood.
Antioxidant Activity As well as cholesterol-lowering, studies also suggest saponins have immuno-stimulatory and anti-cancer properties, the latter appears to be the result of its antioxidant activities.
Saponins are found primarily in legumes, with the greatest concentration occurring in soybeans.
VanadiumVVanadium has only recently been recognised as being beneficial to human health.
Mimicking Insulin The main benefit appears to be its ability to improve or mimic the action of insulin. Insulin is a hormone secreted by the pancreas in response to increased blood glucose levels (such as found after a meal or high sugar snack). It functions by stimulating the cells of the body to absorb glucose from the bloodstream. A decreased response to insulin can result in type 2 diabetes.
Parsley contains extremely high amounts. Other good sources include lettuce and radish.
ChromiumCrChromium is known to be an essential micronutrient, being required for the synthesis of essential biological molecules, such as fatty acids and cholesterol (yes, cholesterol is an essential molecule). It also has a role in regulating blood sugar levels by enhancing the effects of insulin, a hormone secreted by the pancreas in response to increased blood glucose levels (such as found after a meal or high sugar snack). It functions by stimulating the cells of the body to absorb glucose from the bloodstream. A decreased response to insulin can result in Type 2 Diabetes.There are no official figures for the chromium content of fruit and vegetables, but root and bulb vegetables such as onions, potatoes, carrots and parsnips are potentially good sources, although it will depend on the chromium content of the soil.Refining of food leads to a dramatic drop in chromium levels compared to fresh produce.
Vitamin DCholecalciferolVitamin D is not found in plants, so natural sources in the diet are provided by milk, eggs, butter, fish and liver. However many foods in the UK are fortified with vitamin D such as margarine, breakfast cereals and milk. Vitamin D is targeted to three main tissues in the body - the intestines, the kidneys and bone. In each tissue it has the same effect - to raise the levels of calcium in the surrounding fluid (plasma). In the intestines it stimulates the absorption of calcium and phosphorus from the digestive tract, whilst in the kidneys it promotes recovery of calcium from the urine. Its role in the bone is a little more complex, but it is involved in the reabsorption and release of bone calcium dependent on the need of the other tissues of the body.Vitamin D does not conform to the usual definition of a vitamin because the body can make it in the skin when exposed to sunlight. So active gardeners need not be worried by deficiency.
CobaltCoCobalt is essential by virtue of the fact it is an integral part of vitamin B12.Since vitamin B12 is virtually absent from plants (although it is present in some mushrooms) there is little point to trying to increase cobalt concentrations in the soil.
ZincZnZinc is a cofactor for over 100 enzymes in the body, especially those involved with the metabolism of protein, carbohydrate, fat and alcohol. It is essential for growth, development and sexual maturation. It aids wound healing and the development of a healthy immune system.
Cold Cure It is often quoted that zinc supplements can reduce the length of a cold, although despite numerous studies, the scientific jury is still out.
Sources of Zinc It should be said that fruit and vegetables are not particularly good sources of zinc, but that legumes and cereals can be a good source of phytate which can inhibit the absorption of zinc by the digestive tract. Many cases of zinc deficiency occur in vegetarians who use pulses and other legumes as a main source of protein.
Soils that may suffer from low zinc: sandy and acidic or alkaline and rich in humus. Soils excessively high in phosphorous, nitrogen, calcium, or aluminium. Plant signs of deficiency are similar to nitrogen deficiency with rolled leaf margin and pale or greyish, yellowing between veins (chlorosis) that shows up first in young leaves, which are also reduced in size. Zinc deficiency is rare, but levels can be increased by the application of a seaweed-based fertiliser.
PotassiumKPotassium is a macromineral which is essential for cell and tissue function. It is a major component of the fluid inside and bathing cells where it has an important role in regulating the acid/alkali balance, which provides a stable environment for the functioning of enzymes in the cell. Disruption of this balance can have a dramatic effect on the body leading to death.Soils that may suffer from low potassium: Sandy soils; acidic soil; soils high in peat. Soils containing excess calcium or magnesium. Plant signs of deficiency are the appearance of yellow translucent spots and browning on older leaves at the leaf margins. Potassium levels can be increased by the application of bone meal or a seaweed-based fertiliser.Potassium is very soluble and considerable amounts may leach into the cooking water. Like all minerals, potassium is stable to heat and freezing, but may be lost during thawing.
It is a common sight in the UK to see arthritis sufferers wearing copper bracelets to ease the symptoms of their condition. This may reflect the role of copper as an essential cofactor of one of the body's natural antioxidants, super oxide dismutase, which can help reduce the symptoms of inflammatory diseases.
Copper Deficiency One of the major symptoms of copper deficiency is anaemia due to its role in the transport of iron to the regions of red blood cell formation. Copper is also involved in the synthesis of the pigment melanin, which is not only involved in contributing to eye and hair colour, but also in pigmentation of the skin giving protection from expose to the sun's UV rays.
Fruit and vegetables used to be a rich source of copper due to the use of copper-based fungicides, however consumer pressure to reduce the use of such chemicals has led to a fall in the level in horticultural produce. Soils that may suffer from low copper levels: Peat soils. Excess phosphorus, zinc or nitrogen. Plant signs of deficiency include the centre of the leaves yellow while veins and leaf margins remain green. Shoots tips die, leaves may fail to develop. The level of copper can be increased in their soil by the use of organic fertilisers and irrigating with soft tap water that is supplied through copper pipes.Soft tap water supplied through copper pipes may increase amounts present in food when used for cooking, as may the use of copper cooking vessels. Processed foods tend to be low in copper content.
Vitamin ETocopherols & TocotrienesIt is difficult to state that vitamin E (Tocopherol) is essential, as it is found is so many foods, however it is becoming clear that vitamin E is probably the most important ingested antioxidant in the body. And it is this property which is thought to be behind the evidence that vitamin E can lower the rates of cancer and cardiovascular disease (heart attack and stroke) in human.
Heart attacks & strokes The evidence that vitamin E can reduce the risk of contracting cardiovascular disease is unsurprising, since vitamin E is transported in the blood in low density lipoproteins. Low density lipoproteins are also the transport vehicle of cholesterol, oxidation of which leads to narrowing of the arteries a major component leading to heart attack and stroke - the other being blood clots. A regular intake of vitamin E loads the low density lipoproteins with this antioxidant which helps protect cholesterol from oxidation.
Diseases of the Nervous System Vitamin E has a second important antioxidant role - it protects cell membranes. Cells are surrounded by a membrane which keeps the inside in and the outside out. There are also membranes inside the cell that divide the space into compartments termed organelles. Organelles are a little like rooms in a house - each has their own function, the tools required to do that function are stored there and incompatible activities are separated. In this way both the house and the cell can operate efficiently. If you removed the walls of a house you would soon find the garage spilling into the kitchen or the bathroom overflowing into the bedroom. A similar situation exists if the cell membranes start to breakdown, it cannot contain the chemical reactions it needs to do in their specialised compartments and chaos ensues leading to death of the cell. Vitamin E helps protect cell membranes from damage, allowing the cell to function efficiently. A good example of the function of membranes is nerve cell function. Nerve cells need to be able to separate sodium from potassium in order to function. A lack of vitamin E leads to various diseases of the nervous system particularly in the extremities. There are eight chemical forms of vitamin E, the most important of which is a-tocopherol. This is underlined by the fact that a-tocopherol is the only form to be found in animal tissues. Plants contain all eight forms and the philosophical basis of the 5 A DAY campaign would certainly suggest that we should not underestimate the importance of the other seven.
Vitamin E, like other fat soluble vitamins, is transported from the cells lining the intestines to the liver for processing in the lymph system. Unlike the circulatory system which has its own dedicated pump - the heart - to push the blood around the body, the lymph system relies on everyday movement i.e. exercise. Amateur gardeners can thus take pleasure in the knowledge that the vegetables they produce are not only supplying this important vitamin, but by tending their plot they are ensuring the body can get the maximum benefit of its antioxidant properties.The very high temperatures of frying can destroy vitamin E. Some losses also occur during freezing, thawing and commercial food processing.
Phytosterol Phytosterols are analogues of cholesterol that can reduce the absorption of cholesterol from the diet by competing for uptake. Their presence may also reduce the rate of cholesterol synthesis by the body by fooling the body it to thinking its levels of cholesterol are higher than reality. These two factors may lead to a decrease in the levels of cholesterol in the blood.
Cardiovascular Disease High levels of cholesterol in the blood has long been recognised as a major contributory factor to the development of cardiovascular disease. It is thus suggested that phytosterols may lower the risk of contracting cardiovascular disease. Importantly these compounds do not appear to effect the absorption of fat-soluble vitamins.
Phytosterols occur in almost all plant species, particularly in green and yellow tissues.
BoronBBoron has only recently been recognised as important to human health, helping to maintain bones and joints, although its essential role in plants has long been recognised. In man, boron appears to increase bone density by the activation of vitamin D, a vitamin that aids the absorption and utilisation of calcium, although the exact mechanism is unknown.
Treating Osteoarthritis & Preventing Osteoporosis Boron supplementation has been used to treat osteoarthritis. Furthermore, it appears to prevents calcium loss from post-menapausal women, indicating a possible use in preventing osteoporosis. This may be due to a positive effect on oestrogen.
There are no official figures on the levels of boron to be found in fruit and vegetables, however the actual level in produce will depend on its concentration in the soil and the characteristics of the species. There are reports that cauliflower is a particularly rich source. Acid soils and sandy soils with low organic matter are often deficient in boron. Plant symptoms of deficiency include: leaves become thick, leathery and discoloured. Plants fail to bloom. Growing tips die. Rust-coloured cracks develop in stems and leafstalks. Soil concentrations can be raised using organic fertilisers.
Vitamin B1ThiaminVitamin B1 or thiamin is essential for a happy and active life, being essential for both energy production and a positive outlook. It is an essential co-factor to the enzyme pyruvate dehydrogenase which controls the flow of sugar-derived molecules in to the Krebs cycle, a set of chemical reactions that produces 90% of the energy we get from sugar in our diet.
Effects of Deficiency Deficiency causes mental depression, memory confusion and impairment in acquiring new information or establishing new memories and in retrieving previous memories (amnesic syndrome). Pyruvate dehydrogenase produces a compound called acetyl coenzyme A which, as well as entering the Krebs cycle, is also required to manufacture the neurotransmitter acetylcholine. Neurotransmitters convey messages around your brain and a deficiency will obviously effect brain function.
Seeds are often a rich source of thiamin - after all they need plenty of energy to germinate and get established as a functional seedling.Thiamin is unstable when heated and is generally lost in processing, freezing and thawing. It is a water-soluble vitamin and is leached out into cooking water. Vitamin C can protect thiamin from being oxidised in some foods.
FluorineFIn 1968 37% of the UK population had no teeth compared to just 13% in 1998. Most of this improvement can be contributed to fluoride. Fluorine in the form of fluoride is essential for the production of hard decay-resistant teeth, it alters the form of calcium phosphate crystal termed apatite to give fluoroapatite. Calcium fluoroapatite is a harder substance than apatite and is more resistant to decay. Fluoride also helps protect the teeth in other ways. When you eat sugar-rich foods your mouth becomes acidic - a process that can lead to the teeth starting to demineralisation (a similar process to de-scaling your kettle with vinegar). Fluoride not only accelerates the remineralisation of the teeth, but also changes the mouth flora to reduce the amount of acid produced. The richest natural plant sources of fluoride are seaweed and black tea, although in the UK by far the greatest source is from fluoride in toothpastes.For the amateur grower fluoride levels in home-grown produce is dependent on the soil composition. Irrigation with fluorinated tap water may lead to an increase in the fluoride content of produce, along with the use of seaweed-based fertilisers.Content of food may be enhanced by cooking in fluorinated tap water.
IodineIDerbyshire neck or goitre was a common complaint in the peak district and some parts of the Midlands pre-WWII and was caused by a lack of iodine in the diet.
Effect on Thyroid Hormones Iodine is an essential component of the thyroid hormones, thyroxine and triiodothyronine, and lack of iodine causes the thyroid gland to swell as it searches for iodine in the blood. This condition is rare now as milk in the UK and table salt elsewhere is often fortified with iodide, although current nutritional advice suggests that we reduce the quantity of both salt and dairy products in the diet.
Iodine is not essential for plant growth and in general plants contain very little.
Main Sources of Iodine The main natural reservoir of iodine is the sea and consequently seaweed and seafood is a good source. On land it tends to be found in soils that were once covered by the sea and explains nicely why peak district soils are deficient. For the amateur gardener a seaweed-based fertiliser is the best way to raise iodine levels in the soil.
Iodonised salt in cooking water will increase the concentration in foods.
Vitamin B6PyridoxineVitamin B6 or pyridoxine is a water soluble vitamin that is essential for the production of proteins and so is essential for growth and development. It is also essential for processes that require large amounts of protein production such as haemoglobin (the pigment in red blood cells) and antibodies (vital for an active immune system). It is also be involved in the conversion of linoleic acid to other essential fatty acids and prostaglandins (hormone-like molecules that maintain blood vessel health).
The Nervous System Vitamin B6 is required for proper functioning of the nervous system. It is required to synthesise some amine-derived neurotransmitters (compounds that allow brain cells to talk to each other) such as serotonin, a lack of which is linked to depression and melatonin, the hormone needed for a good night's sleep.
Cardiovascular Disease Vitamin B6 may also reduce the risk of developing cardiovascular disease by participating in the metabolism of homocysteine, an amino acid that can directly damage blood vessels and has been correlated with an increase risk of heart attack and stroke.
The highest level of vitamin B6 from plant sources often comes from the seeds. Not surprising when you consider how much protein synthesis an embryo requires to germinate and form an independent seedling.Pyridoxine is a water-soluble vitamin and can be leached into cooking water. It is also destroyed by thawing. Convenience food often contains low levels of vitamin B6, since processing can destroy significant amounts.
Vitamin ARetinolPlants do not contain vitamin A (retinol), but a related compound called beta-carotene. Many of you will know beta-carotene as the orange pigment in carrots and sweet potato and it consists of two molecules of retinol. The human body is able to convert beta-carotene into retinol, hence it is often called pro-vitamin A. Vitamin A is an antioxidant, although its main functions are in sight, growth and development.
Vision Many people will have heard the saying "carrots help you see in the dark" - allegedly used as propaganda to convince the German high command during WWII that RAF success was due to keen eyesight and not the invention of radar. Retinol is an essential component of the protein that detects light in the eye and without it sight is impaired, especially at night; a condition we term night blindness. A measure of one's vitamin A status is how quickly one's vision adapts to a darkened room.
Anti-cancer Vitamin A's anti-cancer role is attributed to its antioxidant activity, however it may be due to more than that - most cancers actually form from epithelial layers. Epithelia are the thin layer of cells that cover most of the body's surfaces and as such are usually the first line of defence against attack from pathogens. Epithelia - Vitamin A role in development is in the proper formation and functioning of epithelia. This also explains vitamin A's role in the defence against disease. In the form of retinoic acid it stimulates the secretion of mucus ,keeping these linings washed and lubricated. Deficiency leads to conditions such as dryness of the eye's surface epithelia (conjunctiva) with a decreased ability to fight infection and consequently an increased risk of conjunctivitis.
Effect on bones Vitamin A is involved in the remodelling of bones that occurs during normal growth and development. Bones are dynamic with calcium being laid down and reabsorbed throughout the first 35 years of life. Vitamin A deficiency during this period can lead to the thickening of bones.
Toxicity The biggest advantage of obtaining vitamin A in the diet as beta-carotene is that it avoids the possibility of overdoses. Retinol can be extremely toxic in large amounts. Retinol is a fat-soluble vitamin and unlike water-soluble vitamins its concentration in the blood cannot be regulated by excretion via the kidneys. Consequently retinol remains in the body until utilised and if too much is present in the diet, toxic levels can be reached. Concentrations of only ten times the recommended dose can lead to headaches, dry skin, hair loss and joint pain. Intakes above 300mg can have serious effects including liver and bone damage, hair loss, double vision, vomiting, headaches and other abnormalities. Beta-carotene, however, is only converted to retinol (theoretically yielding two molecules, but in practice only one) by the body when required avoiding the toxic effect. Beta-carotene itself is also stored in the body, but there are no toxicity problems, just the obvious side effect of turning the skin orange - a condition termed carotinosis which gives a similar effect to cheap tanning lotions.
Orange vegetables are a good source of beta-carotene.Cooking often makes beta-carotene more available to the body by increasing its solubility, particularly if cooked in the presence of fat/oil.
Cysteine Sulphoxides Cysteine sulphoxides are found in allium species. In the plant they act as stores of nitrogen and sulphur until the plant is attacked (eaten), where they under go a chemical change to form the pungent flavours we all associate with alliums. The chemical change is catalysed by alliinase, an enzyme that is inactivated by heat. This is why if you bake a whole onion it only tastes very mildly of onion because the alliinase is destroyed, leaving the more or less tasteless cysteine sulphoxides intact.
Effect on Blood and Some Cancers Chemical cleavage of cysteine sulphoxides results in a number of thiosulphinate compounds that undergo further change to potentially produce dozens of different compounds. It is these compounds that are thought to be beneficial to human health, having a number of effects including thinning of the blood (onion and leek) and the reduction is some forms of cancer (garlic).
Smell of Garlic Allicin, the cysteine sulphoxide derivative of garlic, is one of the only bioactive compounds we can be certain reaches all tissues of the body, since many people have observed the smell of garlic emanating from the skin. The most often commented effect of eating garlic however is garlic breath, but even this indicates the potency of allicin in reaching all tissues of the body. This is because the odour actually comes form the lungs and not the stomach, and it gets there via the blood. If a compound is in the blood then you can be assured that it has had access to every part of the body. Indeed it is even said that if you place a crushed clove in your sock, your breath will start to smell of garlic.
Allium roots are generally pathetic with the plant relying on making mycorrhizal associations. Organic foliar feedants may help improve the nutrient density in these plants.
MolybdenumMoMolybdenum deficiency has only occasionally been observed in humans and so a clear idea of the effects of deficiency is unavailable. However the roles of molybdenum as a cofactor in three enzymes, one of which is vital for metabolism, suggests that this micromineral is probably essential. These three enzymes are: sulphite oxidase, xanthine oxidase and aldehyde oxidase. Sulphite oxidase is an essential enzyme involved in the metabolism of the sulphur-containing amino acids, cysteine. Sulphur is an essential element in many biological molecules, including nearly all proteins. The digestive tract is not very good at absorbing sulphur and so the body obtains it from sulphur-containing amino acids in the diet. Sulphite oxidase is involved in making the sulphur in cysteine available for use in other metabolic processes. Xanthine and aldehyde oxidases are involved in the breakdown of drugs and toxins. Xanthine oxidase catalyses the breakdown of nucleotides (precursors to DNA and RNA) to form uric acid, which contributes to the antioxidant capacity of the blood.Most of the information contained in these pages concerns the problems associated with poor human nutrition and how a diet rich in fruit and vegetables can help avoid insufficiencies in essential nutrients. However, it is obvious that a soil rich in minerals also helps avoid poor nutrition in plants. Below is an example of how poor plant nutrition can have knock-on effects on humans.
Gastroesophageal Cancer Linxian is a small region in northern China where the risk of contraction oesophagus and stomach cancer is increased compared with the average Chinese citizen. The soil in this region is deficient in molybdenum and so dietary molybdenum is also low. Plants require molybdenum to synthesize nitrate reductase, a molybdoenzyme necessary for reducing nitrate to amino acids. When soil molybdenum content is low, plant conversion of nitrates to nitrosamines increases, resulting in increased nitrosamine exposure for those who consume the plants. Nitrosamines are known carcinogens and increased intake may be one of the factors that contribute to the development of gastroesophageal cancer in this population. Soils that may suffer from low molybdenum: Acidic soils. Excess sulphur or copper. Plant signs of deficiency include: Growing points die, leaf margins of young plants yellow and curl. Older leaves become abnormally large, while young leaves remain very small. Applying an organic fertiliser may help raise soil levels.
PhosphorousPPhosphorous is the second most common mineral in the body after calcium, found almost exclusively as phosphate. Its link with calcium is so strong that the recommended intake is set to match calcium needs molecule for molecule.
Essential Roles in the Body Phosphorous has many roles in the body. It is a structural component of bone, nucleic acids (DNA & RNA) and cell membranes; the latter two being essential for cell function. It is essential for energy production and storage. Phosphorus also helps to maintain normal acid-base balance (pH) of cells and tissues such as the blood. A number of enzymes, hormones and cell-signalling molecules are also dependent on phosphorylation (the addition of phosphate) for their activation. Phytic acid or phytate is a form of phoshorous (inositol hexaphosphate) found in legumes, cereals and nuts that can reduce the absorption of calcium, iron and zinc by forming insoluble salts.
Soils that may suffer from low phosphorous: Cold, wet or very acidic (below pH5) soils, peat soils, sandy soils; also very alkaline soils (above pH 7.5). Plant signs of deficiency include: Plants become dark green frequently changing to purple, especially the undersides of leaves. Leaves then yellow. Phosphorous is often unavailable in many soils being locked up in insoluble forms. This has led to its regular application to farmed soils in the form of NPK fertiliser. However, regular applications are often needed, as the soluble phosphate is soon made unavailable. Many plants have evolved their own way of accessing unavailable phosphate by forming mycrorrhizal associations. Encouraging soil microflora is a good way of ensuring phosphate availability to your crops.High levels may be found in hard cooking water.
Vitamin B9FolateFolate is an essential B vitamin involved in many reactions in the body. The latest scientific evidence suggests that it may reduce the risk of contracting cancer, cardiovascular disease and neural tube defects in unborn children.
DNA Repair & Cancer It is thought that one cause of cancer is when a cell containing damaged DNA divides into two before the DNA is repaired. This results in changes to the DNA code that may result in genes being expressed at inappropriate times leading to cancer. Any factor that delays DNA repair, such as a insufficiency of folate resulting in a shortage of DNA components (in this case the purine and pyrimidine bases), can lead to such a change in the DNA sequence. Folate may be involved in a second possible cause of cancer - changes in epigenetic control. Just because a cell contains a gene doesn't mean it will use it. There is increasing evidence that genes can be shutdown by methylation of the DNA - a process that requires folate. It has been suggested that the shutdown or reactivation of genes in an uncoordinated manner may lead to cancer.
Many vegetables are very rich sources of folate with asparagus, beetroot and Brussels sprouts supplying over 50% of the recommended nutrient intake in one portion.Folate is unstable at high temperatures. Keeping food hot or reheating can be particularly damaging, leading to the loss of all the vitamin B9 present. Folate is less soluble in water than the other B vitamins, but losses can still occur by leaching into cooking water.
CarotenoidsTetraterpenoidsThe use of carotenoids in plants is limited compared to animals and yet most animal carotenoids are plant derived. They are often responsible for the yellow, orange and red colours we find in plants and give colour to many of the most commonly eaten vegetables such as carrots and tomatoes and generally the more intense the colour the more they contain.
Antioxidants The main carotenoids found in plants are: a-Carotene, beta-Carotene, beta-Cryptoxanthin, Lycopene, Lutein and Zeaxanthin. Their main biological function appears to be to act as antioxidants, limiting cellular and tissue damage when metabolism goes wrong or the body is attacked by toxins. This antioxidant activity explains why carotenoids may lower the risk of contracting some age-related and lifestyle-related diseases such as cardiovascular disease and cancer.
Plant phytochemicals Lutein and zeaxanthin are a very good example of how animals often hijack the function of plant phytochemicals. They are concentrated in the chloroplasts, the green organelles of plants that capture light energy to produce energy which they use to build sugars from carbon dioxide and water - a process called photosynthesis. Light however can be dangerous; many of us will be aware of the power of some lasers or the damage that can be caused to the skin by over-exposure to the sun. Plants have a similar problem - photosynthesis sometimes goes awry and damage can result, so plants pack the chloroplasts with lutein and zeaxanthin to minimise the damage by acting as antioxidants. It is thus not surprising that in the human body the highest concentration of lutein and zeaxanthin are found in the macular region of the eye where it is suggested that they may reduce the rate of age-related eyesight deterioration. Lutein and zeaxanthin can not be synthesised by the human body.

The 5 A DAY mantra Eatin a wide range of different coloured fruit and vegetables is the best way to maximise carotenoid content and diversity in the diet.
Vitamin KPhylloquinone & MenaquinoneVitamin K deficiency is rare, being most common in new-born babies. Vitamin K is involved in the proper clotting of blood, formation of bones and brain function. Vitamin K has a major role in the activation of a group of proteins called "gla-proteins".
Blood Clotting System Several components of the blood's clotting system are gla-proteins (specifically prothrombin, factors VII, IX and X) and hence explain the manifestation of vitamin K deficiency as an inability of the blood to clot. The drug warfarin, often given to people where the risk of forming clots that could lead to heart attack or stroke, functions by causing a vitamin K deficiency in the body. Note that high levels of vitamin K intake can overcome the effect of warfarin and similar drugs.
Bone Density Another gla-protein is osteocalcin which is required for the binding of calcium to the bone matrix. It is now recognised that increased vitamin K intakes may help increase bone density in people with osteoporosis. Gla-proteins are also found in the brain and other tissues although their roles are unclear.
Many vegetables are rich sources of vitamin K, many of which supply several times the minimum recommended amount.Vitamin K is heat stable and is not degraded by freezing, thawing or processing.
SiliconSiSilicon is the second most plentiful element on this planet after oxygen with which it combines to form quartz. However, humans only require very small amounts of this micromineral. It has an essential role in maintaining structural tissues such as collagen, bone and cartilage.All soils are rich in silicon and enrichment is not needed.
Flavanols There are four common flavanols in plants: Quercetin, Kaempferol, Myricetin, Isorhamnetin. By far the most studied is quercetin, with a number of potential benefits for health being associated with its inclusion in the diet.
Reducing Symptoms of Allergies Quercetin may help with reducing the symptoms of allergies, asthma and hayfever by inhibiting the production and release of histamine, a substance that promotes symptoms such as a runny nose, watery eyes - the body's attempt to flush out the allergen (allergic substance). Histidine also causes swelling of soft tissue including the face and lips common in severe allergies.
Reducing Risks of Cardiovascular Disease Some population-based studies suggest that quercetin along with other flavonoids such as resveratrol may help reduce the risk of developing cardiovascular disease by inhibiting the plaque build up in the arteries (atherosclerosis). This is attributed to their antioxidant activity which may protect against the oxidative damage of the cholesterol carried in low-density lipoproteins, which is a major factor in artherosclerosis. Flavonoids, like quercetin, may also lower cholesterol levels.
Rheumatoid Arthritis Quercetin's anti-histamine and antioxidant activities may be involved in the improvement reported by people with rheumatoid arthritis who experience an improvement in their symptoms when they switch to a diet rich in plant produce and thus naturally quercetin rich.
Inhibiting Cancer Cell Growth Quercetin and other flavonoids from fruits and vegetables may also reduce the risk of contracting some cancers. Quercetin and other flavonoids have been shown in animal and test tube studies to inhibit the growth of cancer cells, including those from breast, colon, prostate and lung tumours.
The main sources of quercetin are citrus fruits, apples, onions, parsley, tea and red wine. Quercetin is also found in broccoli and kale.
SeleniumSeSelenium has broken new ground in nutrition. Recent research has shown that selenium, although not essential, may have significant benefit to human health including reducing the risk of contracting cancer and cardiovascular disease.Selenium levels in horticultural produce depend on the levels in the soil. Unfortunately large areas of the UK are deficient. Soil levels can be raised by applying seaweed and chicken litter-based fertilisers. Experiments in Finland attempting to raise selenium levels in the diet found that application of selenium fertiliser also improved plant health.
SodiumNaAn essential macronutrient mainly found in the blood and fluids that bathe tissues.
Health Risks from Excess Sodium The main concern in the UK over sodium in the diet is not insufficiency but excess which can lead to an increased risk of developing hypertension, cardiovascular disease and stomach cancer. Vegetables are naturally low in sodium, preferring to use potassium.
Sodium is not an essential element for plants and many only contain trace amounts. Training one's taste buds to appreciate the natural flavour of vegetables is an important step to reducing sodium intake. Soil deficiency is rare with coastal regions often having levels of sodium that can inhibit the growth of some species.Many people add sodium in the form of salt to the cooking water or onto their vegetables directly. Current government guidelines suggest that people refrain from such practices as most diets contain sufficient sodium without supplementation. Many processed foods are rich in sodium.
Glucosinolate Glucosinolates are found in cruciferous vegetables (brassicas) and the mustard family and may activate the detoxification pathways in the liver. Their major role in the plant is to act as anti-feedants, undergoing chemical cleavage when the vegetable is damaged, producing many of the pungent and bitter flavours associated with these crops.
Reducing the Risk of Cancer It is these flavour compounds that are now generating a lot of excitement, as they appear to have some significant effects on human health. The major chemical families derived from glucosinolates are indole derivatives and isothiocyanates and appear to have significant potential to lower the risk of contracting certain forms of cancer.
Most Beneficial Effects Glucosinolate derivatives appear to have four beneficial effects: They alter detoxification pathways, reducing the production of cancer-causing compounds (carcinogens). They are antioxidants, helping to neutralise oxidants. They appear to be able to slow the growth of some tumours and in some case cause the tumour cells to die. They can alter the action of oestrogens and so may lower the risk of oestrogen-promoted diseases.
To get the maximum benefit form glucosinolates and their derivatives, eat a wide range of brassicas and other crucifers as they all appear to have different combinations of variants - the medical values of some of which are yet to be investigated, but are likely to be significant. Ensure maximum glucosinolate levels in your crop by ensuring your soil is not sulphur-deficient.Glucosinolates are present in relatively high concentrations in cruciferous vegetables, but cooking, particularly boiling and microwaving at high power, may decrease the bioavailability of isothiocyanates.