Recommended Daily Allowances for Vitamins, Minerals and Trace Elements

Governments have set recommended guidelines for the daily levels of nutrients that an ‘average’ healthy person requires from her diet. Recommended Dietary Allowances (RDAs) were established in the US in 1941 to serve as a goal for good nutrition. The figures are periodically revised, and are judged to be adequate to meet the nutritional needs of most healthy people. Comprehensive breakdowns of RDAs by age and sex exist for each vitamin and mineral, but, for the sake of simplicity, most charts only list the RDAs for an adult male.

It should be remembered that government recommendations are very conservative, aimed only at keeping a person well-nourished and keeping at bay deficiency diseases such as rickets (see pp.310-13). These RDAs are much lower than the ‘optimum’ levels recommended by some nutritionists to boost the immune system and prevent degenerative diseases such as cancer and heart disease.

Vitamin and mineral amounts are expressed in milligrams (one-thousandth of a gram) or micrograms (one-thousandth of a milligram). These are abbreviated to mg and meg respectively.

VITAMIN AND MINERAL CHARTS

The following charts include the US Recommended Daily Allowances (RDAs), which are used throughout Europe. The foods listed under the ‘good sources’ heading are ordered in terms of their nutrient content, with the first food item in the list being the richest source.

Vitamin A (from retinol in animal foods; or from beta-carotene in plant foods)

GOOD SOURCES:

Retinol: liver, egg yolk, fortified margarine, cheese, full-fat milk, oily fish, butter; beta-carotene: carrots, cantaloupe melon, green leafy vegetables, mangoes, apricots, papaya.

ROLE:

Essential for growth and cell development, vision and immune function; maintains the health of the skin and mucous membranes, such as the lining of the respiratory and urinary tracts. Beta-carotene is considered an important antioxidant.

RDA: 800mcg

SYMPTOMS OF DEFICIENCY:

Poor night vision, frequent colds or infections, respiratory disorders, dry, flaky skin.

Vitamin B1 (thiamin)

GOOD SOURCES:

Pork, kidneys, fortified white bread, liver, nuts, pulses, wholegrain bread, wholegrain cereals, fortified breakfast cereals, potatoes, heart.

ROLE:

Needed to obtain energy from carbohydrates, alcohol and fats; prevents the build-up of toxic substances in the body that may damage the heart and nervous system.

RDA: 1.4mg

SYMPTOMS OF DEFICIENCY:

Loss of appetite, fatigue, irritability, mental confusion, poor sleep, nervous disorders, muscle weakness; deficiency is common among alcoholics.

Vitamin B2 (riboflavin)

GOOD SOURCES:

Eggs, milk (if packaged so that it is not exposed to sunlight), yoghurt, fish, fortified breakfast cereals, meat and poultry.

ROLE:

Needed to release energy from food and for the functioning of vitamin B6 and niacin; needed to repair and maintain healthy skin; important for hair, nails and eyes.

RDA: 1.6mg

SYMPTOMS OF DEFICIENCY:

Dry and cracked lips, sore tongue, red itchy eyes, mild anaemia, burning sensation in the feet.

Vitamin B3 (niacin)

GOOD SOURCES:

Liver, oily fish, fortified breakfast cereals, poultry, potatoes, pulses, nuts, sunflower seeds and eggs.

ROLE:

Essential for energy production, brain function and the skin; helps to maintain an efficient digestive system; helps balance blood sugar and control cholesterol levels; vital for a healthy nervous system.

RDA: 18mg

SYMPTOMS OF DEFICIENCY:

Fatigue, depression, irritability, headaches, dermatitis, diarrhoea and, in advanced cases, dementia.

Vitamin B5 (pantothenic acid)

GOOD SOURCES:

All meat and vegetable foods, particularly liver, dried fruit, whole grains and nuts.

ROLE:

Helps to release energy from food and controls fat metabolism; helps to maintain normal blood-sugar levels and increase energy, particularly in stressful situations; helps to make anti-stress steroid hormones and important brain chemicals.

RDA: None set, but 6mg is a safe, adequate dosage.

SYMPTOMS OF DEFICIENCY:

Stress, irritability or depression, dizziness, fatigue, numbness and tingling in the toes.

Vitamin B6 (pyridoxine)

GOOD SOURCES:

Wholewheat cereals, yeast extract, bananas, fish, poultry, nuts, soya beans, lean meat, offal, eggs and wholewheat bread.

ROLE:

Helps to digest and utilize proteins, prevent cardiovascular disease, maintain immune function, hormonal balance and a healthy nervous system; helps form red blood cells.

RDA: 2mg

SYMPTOMS OF DEFICIENCY:

Anaemia, depression, water retention, nervousness and confusion.

Vitamin B12 (cyanocobal-amin)

GOOD SOURCES:

Found only in significant quantities in animal foods, especially kidneys, liver, sardines, fish, eggs and cheese; non-animal food sources include fortified breakfast cereals, tofu and seaweed.

ROLE:

Needed for the manufacture of genetic material (DNA and RNA), which exists in every cell; involved in energy metabolism and immune function; helps to form red blood cells and maintain a healthy nervous system.

RDA: 1mcg

SYMPTOMS OF DEFICIENCY:

Anaemia, depression, pins and needles and loss of sensation in the limbs, degeneration of the nervous system; vegans and strict vegetarians are advised to take B12 supplements.

Biotin (part of the vitamin B complex)

GOOD SOURCES:

Fortified foods such as yeast extracts, egg yolk, liver, brown rice, wheatgerm, milk, nuts and peanut butter.

ROLE:

Needed to release energy from food; important in the synthesis of fat and cholesterol; helps to maintain skin in a healthy condition.

RDA: None set, but 30-100mcg is a safe, adequate dosage.

SYMPTOMS OF DEFICIENCY:

Deficiency is rare, but can be induced if raw egg whites are eaten regularly; symptoms include dermatitis, hair loss, fatigue and muscle pains.

Folate (folic acid; part of the vitamin B complex)

GOOD SOURCES:

Broccoli, green leafy vegetables, pulses, Brussels sprouts, liver, fortified breakfast cereals, wheatgerm, sesame seeds, oranges and nuts.

ROLE:

Required for cell division and the formation of genetic material (DNA and RNA); together with vitamin B12, it is crucial for the production of red blood cells.; essential for brain and nerves – extra folate is needed before conception and in early pregnancy to protect against neural tube defects in the child.

RDA: 200mcg (400mcg in pregnancy).

SYMPTOMS OF DEFICIENCY:

Anaemia, lack of energy, loss of appetite, depression; women with low levels of folate at conception have a much higher risk of giving birth to a baby with spina bifida.

Vitamin C (ascorbic acid)

GOOD SOURCES:

Fruit and vegetables, particularly broccoli, blackcurrants, strawberries, kiwi fruit, citrus fruit, tomatoes and peppers.

ROLE:

Needed to make a protein called collagen which is essential for healthy gums, teeth, bones, cartilage and skin; important as an antioxidant in the body; strengthens the immune system and fights infections; helps to make energy and anti-stress hormones; aids absorption of iron from plant food.

RDA: 60mg

SYMPTOMS OF DEFICIENCY:

Fatigue, aching joints, sore gums, slow wound healing, easy bruising, frequent colds.

Vitamin D (calciferols)

GOOD SOURCES:

Vitamin D is known as the ‘sunshine vitamin’ because it is manufactured by the body when the skin is exposed to sunlight; food sources are limited; it is found in the oil of fatty fish and in cod liver oil, as well as in eggs and fortified margarines.

ROLE:

Needed to absorb calcium and phosphorus from food, both of which are vital for strong bones and teeth; helps to maintain a healthy nervous system.

RDA: 5mcg

SYMPTOMS OF DEFICIENCY:

Joint pain or stiffness, muscle weakness and tenseness, softening of the bones, causing bone pain and a higher risk of fractures; leads to deformation of the skeleton, known as rickets in children and osteomalacia in adults.

Vitamin E

GOOD SOURCES:

Vegetable oils, green leafy vegetables, seeds, wheatgerm, nuts, whole grains and cereals, sunflower spreads.

ROLE:

Antioxidant that binds oxygen and protects the fats in the body from the damaging effects of uncontrolled oxidation and free radicals; helps to protect the body from common pollutants; improves wound healing and fertility and reduces the risk of heart disease.

RDA: 10mg

SYMPTOMS OF DEFICIENCY:

Fatigue and premature ageing, circulatory disorders such as varicose veins, slow healing of wounds, nerve damage.

Vitamin K

GOOD SOURCES:

Green leafy vegetables, especially spinach, Brussels sprouts, cauliflower, lettuce, cabbage, watercress and broccoli.

ROLE:

Needed for normal blood clotting; helps to prevent internal haemorrhaging; essential in forming certain proteins needed for healthy bones and tissues.

RDA: 80mcg

SYMPTOMS OF DEFICIENCY:

Delayed blood clotting of wounds, haemorrhages such as nose bleeds.

Calcium

GOOD SOURCES:

Milk and dairy products, seeds, tinned sardines with bones, nuts, green leafy vegetables and wholemeal or white bread.

ROLE:

Builds bones and teeth and keeps them strong; vital to nerve transmission, blood clotting and muscle functions; regulates heartbeat; helps to maintain a proper acid-alkaline balance; promotes skin health.

RDA: 800mg

SYMPTOMS OF DEFICIENCY:

Muscle aches, leg cramps, tooth decay, soft and brittle bones, fractures and and osteoporosis.

Chloride

GOOD SOURCES:

Table salt and the many foods that contain it.

ROLE:

Works with sodium and potassium in regulating the body’s fluid balance; vital for stomach acid formation.

RDA: None set, but a minimum of 7500mg is a safe, adequate dosage.

SYMPTOMS OF DEFICIENCY:

Deficiency does not occur in a normal diet, except as a result of heavy and prolonged sweating or vomiting.

Magnesium

GOOD SOURCES:

Soya beans, tofu, green vegetables, pumpkin seeds, wholegrain cereals, sunflower seeds, wheatgerm, nuts, pulses and dried figs.

ROLE:

Important constituent of bones and teeth, calms the nervous system; regulates heartbeat; important for muscle contraction; required for normal calcium function.

RDA: 300mg

SYMPTOMS OF DEFICIENCY:

Muscle tremors or spasms, muscle weakness, nervousness, irregular heartbeat, fits or convulsions, lethargy, depression.

Phosphorus

GOOD SOURCES:

Present in all plant and animal protein, such as seafood, fish, milk, cheese, seeds, whole grains, poultry, nuts and red meat. Added to many processed foods, especially soft drinks.

ROLE:

Helps to form and maintain healthy bones and teeth; builds muscle tissue; needed to release energy in cells; essential for absorption of many nutrients.

RDA: 800mg

SYMPTOMS OF DEFICIENCY:

Deficiency is rare but may be induced by prolonged use of antacids (the calcium in antacids can deplete phosphorus); signs include general muscle weakness, loss of appetite, weak and painful bones, rickets.

Potassium

GOOD SOURCES:

Green leafy vegetables, dried fruit, potatoes, bananas, citrus fruit, avocados, pulses, pineapples, nuts and seeds.

ROLE:

Works with sodium to regulate the sodium-potassium balance, which affects water retention and stimulates kidney function; promotes the disposal of the body’s wastes; maintains heart functioning; helps prevent and relieve raised blood pressure; stimulates insulin production.

RDA: None set, but a minimum of 2000mg is a safe, adequate dosage.

SYMPTOMS OF DEFICIENCY:

Weakness, thirst, confusion and fatigue, irregular heartbeat, raised blood pressure.

Sodium

GOOD SOURCES:

Table salt (sodium chloride), tinned anchovies, bacon, crisps, processed meats, tinned vegetables, meat, fish, cheese and breakfast cereals.

ROLE:

Works with potassium and chloride to regulate the body’s fluid balance; promotes sweating and helps to prevent heat stroke; essential for adequate nerve and muscle function.

RDA: None set, but a minimum of 500mg is a safe, dosage.

SYMPTOMS OF DEFICIENCY:

Deficiency is rare because most people in the West consume too much sodium; intense hot weather or sweating copiously will cause deficiency symptoms such as thirst, cramps and muscle weakness.

Copper

GOOD SOURCES:

Shellfish, such as oysters, mushrooms, liver, seeds, nuts, wheatgerm, prunes and wholegrain cereals.

ROLE:

Needed for bone growth and connective tissue formation; helps the body to absorb iron from food; present in many enzymes that protect against free radicals.

RDA: 1.5-3mg

SYMPTOMS OF DEFICIENCY:

Deficiency is rare; only very small amounts are required by the body and even small excesses can be toxic, causing liver and kidney damage.

Iron

GOOD SOURCES:

Iron-fortified cereals, tofu, meat, kidney, liver, pulses, dark-green leafy vegetables, sardines and pilchards, game, egg yolk and prunes.

ROLE:

Essential for the production of haemoglobin, the pigment in red blood cells that transports oxygen to every cell – without iron, body cells would die; promotes energy, prevents anaemia and increases resistance to disease.

RDA: 14mg

SYMPTOMS OF DEFICIENCY:

Shortness of breath, fatigue, iron-deficiency anaemia, reduced resistance to infection, split nails, poor hair growth, sore tongue and mouth ulcers.

Manganese

GOOD SOURCES:

Tea, pineapples, brown rice, wholegrain cereals, tofu, green leafy vegetables, soya beans, pulses, nuts and tropical fruits.

ROLE:

Vital component of many enzymes involved in energy production; helps to form bone and connective tissue; essential for reproduction. Needed as co-factor in the antioxidant enzyme superoxide dismutase.

RDA: None set, but 2-5mg is a safe, adequate dosage.

SYMPTOMS OF DEFICIENCY:

There is no recognized deficiency disorder in humans.

Zinc

GOOD SOURCES:

Oysters, red meat, whole grains and seed foods (beans and peas), seeds and nuts.

ROLE:

Component of some 200 enzymes in the body; essential for normal growth, reproduction, healing and immunity; promotes health of nervous system, as well as the condition of the hair and skin.

RDA: 15mg

SYMPTOMS OF DEFICIENCY:

Loss of appetite, susceptibility to infections, slow wound healing, poor hair growth, acne, dermatitis.

Chromium

GOOD SOURCES:

Nuts, seafood, wholegrain cereals, pulses, red meat and liver, egg yolk, wheatgerm, molasses and cheese.

ROLE:

Important for regulation of blood-sugar (glucose) levels; helps to regulate blood-cholesterol levels.

RDA: None set, but 50-200mcg is a safe, adequate dosage.

SYMPTOMS OF DEFICIENCY:

May cause glucose intolerance and raised blood-cholesterol levels.

Iodine

GOOD SOURCES:

Iodized table salt, seafood, kelp, seaweed and onions.

ROLE:

Needed by the thyroid gland to produce the thyroid hormone, which regulates more than 100 enzyme systems, involving metabolic rate, growth, reproduction and many other essential functions.

RDA: 150mcg

SYMPTOMS OF DEFICIENCY:

An underactive thyroid, resulting from iodine deficiency, can cause symptoms such as goitre (swelling of the thyroid gland) a thick neck, obesity, general weakness, nervousness and irritability.

Molybdenum

GOOD SOURCES:

Liver, wheatgerm, wholegrain cereals, pulses and dark-green leafy vegetables.

ROLE:

Essential component of enzymes involved in the production of DNA; helps liver function, protects the body from the effects of pollution and may fight tooth decay.

RDA: None set, but 75-250mcg is a safe, adequate dosage.

SYMPTOMS OF DEFICIENCY:

Deficiency is virtually unknown.

Selenium

GOOD SOURCES:

Fish, meat, nuts, seeds, avocados, dairy products, lentils, wheatgerm and onions.

ROLE:

Antioxidant mineral; protects cells against free radical damage; stimulates immune system to fight infections; vital for normal sexual development.

RDA: 70mcg

SYMPTOMS OF DEFICIENCY:

Fatigue, susceptibility to infections, premature ageing, predisposition to cancer and low sexual potency.