The Facts About Vitamins
At the beginning of this century a chain of discoveries were made, which could have changed the entire course of medicine, had we been ready for it. These were the discoveries of vitamins A, B and C.
Vitamins are a group of totally unrelated chemicals that have only one thing in common: they are essential (usually in tiny amounts) for the normal functioning of the body. Unlike protein, fat or carbohydrates, vitamins are not used for energy or building materials. Yet without them there can be no energy and no cells. In a sense they are the nuts and bolts that hold us together. They are catalysts, they are regulators and most of all they are essential for life itself.
All vitamins have been given letter codes, sometimes with an additional number to differentiate vitamins within a group. The missing letters and numbers in the series are due to substances initially having been identified as vitamins but later were found to lack the essentials for the classification.
In the last 90 years we have isolated some twenty vitamins, which are classified into two groups. The fat soluble vitamins are vitamins A, D, E, F and K, and the water soluble vitamins include vitamins B, C and P. To maintain and promote health all these vitamins must be present in our diets in the right amounts.
The best way to obtain vitamins is to eat raw, fresh vegetables, fruits, natural grains and legumes. You can't overdose on vitamins. If there's too much in the body it will be excreted. Vitamin A is perhaps the only one that make you feel uncomfortable and there will be obvious warnings signs, but the effect is completely reversed by stopping intake.
There is no evidence that vitamin supplements benefit anyone on a normal diet and in good health. The cheapest and most effective way to obtain adequate vitamins is to eat a well-balanced diet. Most vitamin supplements are expensive, pass rapidly through the body, and merely enrich the sewers.
Do you need supplementary vitamins?
- You are fit and healthy
- You do not smoke
- You have no stress
- You have no psychological hang-ups
- You exercise regularly
- You do not over-indulge in alcohol or drugs
- You eat foods uncontaminated by pesticides, additives or preservatives
- You eat most of your vegies raw or steamed
If you're eating a fairly varied diet it is just about impossible to go short of proteins, vitamins or minerals.
Do you get more than three colds a year?
Are your eyes strained after long journeys?
Vitamin A, also known as Retinol, is a fat-soluble vitamin. Protects our 'inside skin', strengthening it against infection and ulcers, and outside skin, preventing spots. It helps slow down signs of aging. Helps prevent cancer. Is good for the eyes, forms part of pigment in eye. Helps maintain mucous membrane. Is needed to make protein and sex hormones. It also protects our lungs and has been successfully used in the treatment of bronchitis.
While it is essential for the normal function of the skin and eyes, but there is no evidence that extra amounts can improve vision in people with sight problems or can cure skin problems.
High doses of vitamin A (retinol) can be toxic in excess and may cause a disease called carotenaemia which discolors the skin and may cause fetal abnormalities in pregnant women. But a large intake of carotenes (from fruits and vegetables) is not dangerous, but skin can become orange-colored.
The need for Vitamin A rises with a high protein diet or when recovering from infection.
Deficiency Symptoms: Eye problems, bad eyesight, poor night vision, poor hearing, loss of smell, spots, dry flaky skin, oily skin, dandruff, mouth ulcers, throat infections, colds, diarrhea, stuffy nose, stomach or duodenal ulcers, biliousness, depression, anger, frustration, warts, thrush, cystitis, sties, fatigue, loss of appetite.
Common Sources: Milk, butter, cheese, eggs, cod liver oil, liver, enriched margarine, chillies, cantaloupe, bananas, mango. peaches and apricots. Very high levels are found in orange-colored foods (e.g. pumpkin, carrots, pawpaw, etc.)
Destroyed by: Heavy alcohol intake, cigarettes, cooking at high temperatures, clear bottles that allow light through, preservatives in food, use of cortisone and contraceptive pill greatly interferes with absorption. Diabetics cannot convert carotene into Vitamin A so should take cod liver oil.
Recommended Daily Intake: 3000 IU
Do you have difficulty making decisions?
Are you losing weight?
Do you have difficulty breathing?
Vitamin B1, also known as Thiamine, is needed to burn glucose in the cell, creating energy as well as making important nerve chemicals, toning the muscles of the digestive system, and helping in the breakdown of protein. Deficiency therefore affects digestion, energy, and the brain and nervous system. Deficiency symptoms occur among those who eat refined grains, most notably polished rice, and few raw vegetables. B1 helps to release energy from foods, in conjunction with B2 and B3.
Deficiency Symptoms: Tender muscles, stomach pains, constipation, slow irregular heart beat, prickly sensations in the legs, eye pains.
Common Sources: Pork and bacon; liver and kidney; almonds, beans, raw nuts, whole-grain cereals and legumes.
Destroyed by: Cooking, smoking and alcohol.
Recommended Daily Intake: 1.5mg
Are you sensitive to light?
Do you wake up tired?
Vitamin B2, also known as Riboflavin, helps neutralize acidity created when nutrients are burned for energy, reducing over-acidity symptoms like bloodshot, itchy eyes, dull oily hair, eczema, cataracts, and cracked lips. It is also essential for manufacturing the enzymes which break down fats, proteins, and carbohydrates. Helps to release energy from foods, in conjunction with B1 and B3.
Common Sources: Brewer's yeast, nuts, grains, natural dairy products, mushrooms, red peppers and liver.
Deficiency Symptoms: Bloodshot itchy eyes, burning or 'gritty' eyes, sore tongue, cracked lips, cataracts, eczema, dull oily hair, split nails, trembling, sluggishness, dizziness, inability to urinate, vaginal itching.
Destroyed by: Like most B vitamins, thiamine is destroyed by heat and is contained in the germ of grains. Alcohol metabolism also uses up excessive amounts of b2 so alcoholics are usually deficient. B2 is also destroyed by sunlight.
Recommended Daily Intake: 1.7mg
Do you find it difficult to express your feelings?
Do you sometimes feel very energetic and overexcited?
Do you sometimes feel very depressed?
Vitamin B3, also known as Niacin or nicotinic acid, is involved in metabolism and the burning of sugars to form energy, the regulation of blood sugar and histamine levels, and helps keep down blood cholesterol. Because of its many roles it is useful in treating arteriosclerosis, arthritis, acne, depression, hypoglycemia, alcoholism and headaches. Helps to release energy from foods in conjunction with B1 and B2.
Common Sources: Liver, lean meat; raw fish; poultry; whole-grain cereals and legumes.
Deficiency Symptoms: Psychosis, schizophrenia, fatigue, acne, headaches, loss of appetite, migraines, bad breath, skin eruptions, insomnia, irritability, nausea, vomiting, tender gums, depression, rough inflamed skin, tremors, allergies, loss of memory, coated tongue.
Destroyed by: Smoking, diets high in sugars and refined products (white flour, white rice, etc)
Recommended Daily Intake: 20mg. A 'blushing' sensation occurs with doses above 100mg.
Do you find it hard to concentrate?
Do you sleep more than 10 hours a night?
Vitamin B5, also known as Pantothenic Acid, is needed for energy production, fat and cholesterol synthesis, anti-body formation and manufacturing nerve chemicals. It also strengthens the adrenal glands and improves the production of cortisone, increasing resistance to stress. Assists body functions.
Common Sources: Brewer's yeast, organ meats, whole grain cereals, wheatgerm, raw peanuts.
Deficiency Symptoms: Apathy, abdominal pains, restlessness, vomiting, asthma, allergies, burning feet, muscle cramps, adrenal exhaustion, hypoglycemia, exhaustion.
Recommended Daily Intake: 10mg
Do you have difficulty recalling your dreams?
Are you on the Pill?
Vitamin B6, also known as Pyridoxine, makes hormones, enzymes, nerve chemicals and is needed for all metabolism. It also regulates sodium/potassium balance and can relieve symptoms of PMT. Also beneficial for morning sickness, postnatal depression, nervousness, hormone imbalances and allergies. Assists body functions.
Common Sources: Meat; vegetables; pith of citrus fruits (marmalade); wholegrain products, cereals and yeast.
Deficiency Symptoms: Irritability, water retention, bloatedness, hypoglycemia, depression, loss of hair, cracks around mouth and eyes, numbness, cramps in legs and arms, slow learning, morning sickness, postnatal depression, allergies, anemia, nervousness, tingling hands, menopausal arthritis.
Destroyed by: Cooking and the Pill destroy B6.
Recommended Daily Intake: 2mg
Do you have difficulty maintaining balance?
Do you find yourself easily confused or having a poor memory?
Vitamin B12, also known as cobalamin, is needed for building protein and maintaining healthy red blood cells. It is used to treat anemia, tiredness and morning sickness. Essential for formation of new body cells. B12 is the only vitamin containing a mineral, cobalt.
B12 is found in large quantities only in animal protein for vegans. To absorb it an enzyme in the stomach must be present, and it is often a lack of this enzyme that causes deficiency rather than a lack of B12.
Common Sources: Lean meat, especially liver and kidney, brains, tripe, fish and cheese. Absent from plant foods.
Deficiency Symptoms: Nervousness, mental slowness, tiredness, irregular menstrual cycle, body odor. Soreness of the mouth and tongue. Deficiency leads to lower red blood cell production.
Recommended Daily Intake: 6 μg
Do you live in a heavy traffic area?
Is your life style very stressful?
Vitamin C, also known as Ascorbic Acid, is water-soluble and found in citrus fruits, tomatoes and greens. It is essential for the formation and maintenance of cartilage, bone and teeth, and is used in moderate amounts to promote the healing of wounds and during convalescence from prolonged illnesses.
Vitamin C makes collagen, our inter cellular glue, improving condition of the skin and connective tissue. Also activates white blood cells, increasing our resistance to infection and viral invasion. Like vitamin E it protects other substances from oxidizing, and helps detoxify carbon dioxide, mercury, and lead.
Unfortunately there is no evidence to support its use in preventing or treating the common cold.
Common sources: Citrus fruits and especially green vegetables; tomatoes and potatoes.
Deficiency Symptoms: Colds, lack of energy, infections, allergies, arthritis, premature aging, wrinkles, sagging skin, arteriosclerosis, shortness of breath, poor lactation, bad digestion, bleeding gums, cavities, bruising, painful and swollen joints, nose bleeds, slow wound healing, anemia.
Destroyed by: Its level in food is reduced by cooking, mincing and contact with copper utensils. Stress, pollution, cigarettes, the Pill and alcohol increase the need for this vitamin.
Recommended Daily Intake: 60mg.
Do you have pain and stiffness in the joints?
Do you have difficulty losing weight?
Vitamin D, also known as Cholecalciferol, is a fat-soluble chemical found in egg yolks and butter, and it may be formed by a reaction of sunlight on skin.
Vitamin D is necessary for healthy thyroid and parathyroid glands and helps regulate the absorption and distribution of calcium. For this reason it is essential for healthy bones and teeth. Perhaps the lack of sunshine accounts for Britain's extraordinarily high incidence of rheumatism and arthritis.
Deficiency Symptoms: Osteoarthritis, rheumatoid arthritis, rheumatism, rickets, middle backache, muscular numbness, tingling, spasm, lack of energy, tooth decay, hair loss, coarse hair, dry skin, nearsightedness, chilblains, weight problems.
Common Sources: Dairy produce, milk, enriched margarine, egg yolk and cod liver oil. Also produced by action of sunlight on skin. The amount you need depends on your exposure to sunlight, so in winter your need will be greatest.
Recommended Daily Intake: 400 IU
Do you get cramps after or during a long walk?
Do cuts take a long time to stop bleeding?
Do you get out of breath easily?
Is your pulse rate more than 75 per minute?
Vitamin E greatest asset, like vitamin C, is that it protects other substances in the body from oxidizing. It stops the destruction of unsaturated fats, hormones and other vitamins, and by sacrificing itself to these toxic oxides, it leaves the red blood cells supplied with pure oxygen, improving the functioning of the muscles. It also allows the cells to function with less oxygen. For these reasons it is excellent for many heart conditions, and situations in which there is restriction of blood flow.
This vitamin also acts as an anti-coagulant, being good for thrombosis, and is excellent for healing scars. It keeps our cells younger and therefore retards the aging process, also promoting beautiful skin.
People with high blood pressure or suspected heart conditions and chronic rheumatic heart disease patients should only receive vitamin E under medical supervision.
Deficiency Symptoms: Hypertension, high blood pressure, chest pains, anemia, loss of sex drive, rheumatic fever, diabetes, dry skin, easy bruising, infertility, slow wound healing, varicose veins, edema, arteriosclerosis, weak heart, pancreatitis, puffy-ankles.
Common Sources: Seeds; green, leafy vegetables and enriched margarine
Destroyed by: Contraceptive Pill
Recommended Daily Intake: 30 IU
Do you bruise easily?
Do you have bleeding gums?
Do you have extremely heavy menstrual bleeding?
Vitamin K, also known as phylioquinone or phytomenadione, is essential for the clotting of blood. It is fat-soluble and is found in most foods. It is also manufactured by bacteria living in the gut.
A lack is very rare, and high doses may cause anemia in infants and break down blood in adults. It is not commonly used clinically.
Deficiency Symptoms: Deficiency may lead to nose bleeds, miscarriages and internal hemorrhaging of brain, spinal cord, intestines and eyes.
Common sources: Green, leafy vegetables; wholegrain cereals; yogurt, milk, egg yolks, fruits and nuts.
Destroyed by: Failure of liver to supply bile, X-rays, aspirin, air pollution and antibiotics.
Recommended Daily Intake: 80 μg
Why are vitamins essential to health?
Vitamins are simply chemical substances which our bodies need - but cannot make for themselves. They have to be acquired from our food, but only tiny quantities are needed: the total vitamin intake we need each day amounts to less than 100mg (that is, about a 280th of an ounce).
Each vitamin has a very different structure and plays a different role. All have a chemical name, but some are known by a letter/number such as A or B1.
Generally, the B vitamins are involved in chemical reactions which turn carbohydrates and fats in the body into energy. Vitamins A and D have a 'structural' role and help to form and maintain skin and bones. Vitamin C is involved in making collagen which is found in the connective tissues, the packaging material of the body which helps to separate, protect and support various organs. So these vitamins are important in body-building and healing.
If your body isn't getting enough of the vitamins it needs, it stops working so efficiently and you may begin to feel a bit under the weather. But it takes quite a serious deficiency to bring on one of the vitamin-related diseases.
It's also important to remember that eating plenty of vitamins won't compensate for the absence of the other important elements in your diet - the proteins, fats, minerals and carbohydrates - each one is important.
Do you need vitamins every day?
The body holds only a small store of some vitamins, so they need to be taken regularly, although not necessarily every day. This group, known as the water-soluble vitamins, includes the B vitamins and vitamin C. The others are fat-soluble and are stored in the liver; a well-fed adult has enough vitamin D stored to last for many months if necessary, while stores of vitamin A can last for a year or two. A baby is born with a ready supply of vitamin A in its liver to tide it over the first few months of life.
In practice, most people in this country have a good mixed diet which usually provides enough of all the necessary vitamins each day. There may be a shortage of some of the fat-soluble vitamins in one average day's meals, but a simple 'booster' of one of the suitable foods once a week should keep the balance right.
The chart on page 16 quotes the recommended daily intake of vitamins and how it can be supplied. This is enough to cover most people's needs with plenty to spare. For the minor vitamins no daily allowance is stated, but normal diets will automatically provide enough.
Will taking extra vitamins actually make you more healthy?
As long as you are getting enough for your immediate needs in your normal diet, extra vitamins won't make you extra healthy. It's appealing to believe that, since tiny amounts are essential, taking large doses will produce a kind of 'super nutrition' and vitality. But in fact there is absolutely no evidence to support the claims of the 'mega-vitamin' therapists who say that extra vitamins on top of a normal balanced diet give some positive health benefit.
Man has managed to survive until now on the vitamin levels found in normal diets and it's hard to see why his needs should suddenly be much greater just because it's easy to mass-produce vitamins.
Extra vitamins are not used by the body, but are disposed of or stored up. If the vitamins are water-soluble they are simply passed through the system and out the other end; if they are fat soluble, they are stored in the body and remain unused unless daily supplies dry up.
Why do you need vitamin A?
Vitamin A is vital for growth and for renewal of the moist cells which line the various tracts in the body, such as the respiratory and uro-genital tracts and the nasal passages.
It also plays an important role in vision. Your ability to see in dim light is dependent on vitamin A. This vitamin contains a pigment known as rhodopsin (or visual purple}. Certain of the light sensitive cells in the retina rely on this pigment to enable the eyes to adapt to the dark. A deficiency can lead to a condition known as night blindness.
You can assess your own ability to see in the dark by timing how long it takes you to make out the objects in a darkened room immediately after the lights have been switched off. Generally, it should take several minutes for your eyes to become accustomed.
A very severe deficiency can have far more serious repercussions. A condition known as xerophthalmia is caused by a severe deficiency of vitamin A. Although almost unknown in the West, it is the major cause of blindness and mortality in children living in Third World countries. It has been estimated that about 20,000 children go blind annually, and 11 million more are at risk.
Like other parts of the body's surface, the cornea is constantly shedding dead cells and replacing them with new ones. For this process to work smoothly and efficiently, vitamin A is needed. When there are inadequate amounts in the body, the dead cells build up on the surface of the eye, causing it to become dry and wrinkled. If this continues, ulcers may develop which can lead to vision defects. At this stage it can be cured, but when finally the cornea becomes softened, blindness results.
As well as suffering from an overall shortage of foods which provide energy and protein, people of developing countries suffer a deficiency of foods which supply vitamin A. This explains why xerophthalmia is so widespread. Their diets are also often lacking in fat, and, since vitamin A is fat-soluble, this means that even if they were getting enough of the vitamin itself, their diets might still contain less than the 10 per cent of fat necessary to absorb the vitamin A.
Is vitamin A destroyed by cooking?
Being fat-soluble, vitamin A is hardier and not so easily destroyed by cooking as the water-soluble vitamins. If you boil cabbage or carrots you won't destroy their vitamin A goodness, but frying them in oil can cause some loss of nutrients. Similarly, the use of margarine or butter for frying will cause a loss of vitamin A (and a small loss of vitamin D) from these fats. If fish liver oils are stored in glass bottles and exposed to light, a loss of vitamin A will also result. The vitamin A content of vegetables such as peas and carrots is not, however, affected by freezing. But there is a loss of about one quarter of their vitamin A content when vegetables are preserved by canning.
Although many people have some vitamin A each day through eating vegetables which contain it, daily intake of the vitamin isn't essential for health. Because your body is capable of storing it up, it's possible to go for several weeks before you become deficient - providing, of course, you're well nourished to begin with.
Is it true that the B vitamins are especially beneficial to women?
Doctors think that extra vitamin B6 may help to relieve symptoms of pre-menstrual tension. It seems there could be a link between the high levels of the hormone oestrogen associated with PMT and an increased need for vitamin B6 at this time. Supplements of this vitamin have been found to be very helpful in relieving symptoms of depression and tension associated with PMT.
It is also known that large doses of B6 (about 10 times the recommended daily intake) can help post-natal depression. Doctors aren't quite sure how the vitamin acts but since the extra dosage is quite safe and is a preferable form of treatment to potent anti-depressant drugs, it is quite commonly prescribed. There is still much to be discovered about all the vitamins and research constantly goes on into ways they might be substituted for drugs.
How do the B vitamins work?
They work together with substances called enzymes to perform vital chemical reactions in the body. There are many thousands of enzymes involved in carrying out all the life-sustaining processes in the body, and some of them need the B vitamins in order to to their jobs. Without these vitamins, we could not function.
The B vitamins are therefore known as co-enzymes. They trigger off the chemical reactions which produce energy from carbohydrates and fats. Although not in themselves a fuel source, they help to provide the fuel we need to carry out daily activities such as walking, working and playing, and the energy needed for growth and general body maintenance.
Is there any need to take extra B vitamins?
For most people eating any extra B vitamins -above the recommended daily intake - is simply a waste. The excess vitamins will be excreted in the urine. The body's need for B vitamins is rather like the need of a car for oil. If there's not enough oil the engine won't run properly and problems can develop. But once the sump is full of oil it doesn't do any good to pour more into the engine — it will just overflow and be wasted. Since the B vitamins are present in so many foods, you'll meet your daily intake by eating a wide variety of fish, vegetables and cereals.
However, there are some special circumstances when extra B vitamins may be useful, especially in the case of people who are suffering or recovering from a long illness during which they may have eaten very little. The relatively small reserves of B vitamins will be exhausted and, although they could be replenished quite easily from food, it's a useful insurance policy to give supplements in pill form. This will make sure that there is no chance of a slight vitamin deficiency delaying recovery.
It may also be a sensible precaution to take extra B vitamins if you're going in for a crash diet. Most well-planned slimming diets are designed to ensure an adequate intake of vitamin-rich foods but, in the case of people who are trying to lose weight by eating very little, vitamin supplements are essential.
Supplements of one of the B vitamins, folic acid, are usually prescribed for pregnant women. Together with B12, it is essential for the formation of all new body cells, and the demand for it is practically doubled during pregnancy as the foetus grows and develops. Folic acid is also especially important for the formation of red blood cells. If the intake is insufficient to meet the increased demands of pregnancy, the mother may develop a form of anaemia.
Another group of people who may need supplements of one of the B vitamins are very strict vegetarians - the vegans. This is because cyanocobalamin (B12), unlike the rest of the B complex has no plant source and is found only in meat and animal foods. However the problem can be easily remedied by taking preparations of B12 which manufacturers obtain from non-animal sources by growing a type of mould.
Is it true that vitamin C slows down the ageing process?
Sadly, this is just one of the many mythical attributes assigned to this vitamin. It's probably based on the claim that deficiency of the vitamin (which ultimately leads to scurvy) has effects on the body similar to the changes typical of old age - wrinkled skin (due to the loss of the skin's elastic quality), loss of teeth and brittleness of bones. Vitamin C does play an important part in the repair of the body's tissues, but that doesn't mean that taking extra will help slow down the inevitable ageing process.
Vitamin C is essential for the formation and maintenance of collagen, a cement-like substance which holds all the cells of the body together, and forms connective tissue. As such, this protein provides the basic frame-work for both hard tissues (like bone and teeth) and soft tissue (like the membrane of capillaries and the fibrous tissue in scars).
It is true that vitamin C deficiency can make your teeth fall out but only in very severe cases. One of the first obvious signs of scurvy is usually bleeding, swollen gums, followed by gingivitis and loosening of the teeth. Gum tissue fits tightly round the teeth in healthy mouths, but without the essential vitamin, gums become puffy and bleed easily - allowing access to the ever-present bacteria. The supporting framework for the teeth is undermined and they become looser. Within the teeth themselves, the lack of 'cement' slows down or prevents any further development, as it does with bones, although this will only be apparent in a child.
The most obvious signs of scurvy, are bruises, which appear for no apparent reason. Normal blood cells are extremely elastic, and strong, since they must be able to expand and contract on demand. But when there's a vitamin C deficiency, there are changes in all the blood vessels, and especially the capillaries whose walls easily break down, allowing blood to escape into the tissues and show as bruises.
Even before these make their appearance, someone suffering from vitamin deficiency would notice other signs - loss of appetite and weight, muscle and joint pains, and listlessness.
It would take some time for any of these signs to develop, though. The body does have a small store of the vitamin usually, and it would take several weeks (possibly up to as long as four months, or so) without the vitamin for the first symptoms of scurvy to appear. Even then, it can be completely cured just by giving vitamin C. But fortunately, scurvy is rarely seen in this country, except mild cases among particularly vulnerable groups - the elderly, the very young and those in institutions where the diet may be inadequate.
How can you make sure you're getting the right amount of vitamin C?
Since your average daily intake is probably somewhere between 30 to 100 mg of vitamin C per day, it's highly unlikely that you're at risk of being deficient. But there are two schools of thought as to how much vitamin C you should have every day to be in the peak of health.
One school of thought (endorsed by the United States Government), maintains that, ideally, a man ought to be fully saturated with the vitamin so that every cell in his body contains as much as it can hold. This includes filling the small storage capacity which the body has. Once this store is full, any excess is simply excreted - so large amounts of 'extra' vitamin are no use whatsoever. The US government recommendation is that a daily intake of 60mg of vitamin C will maintain tissue saturation; one glass of fresh orange juice (an 8oz glass) provides an average of 130mg. The counter argument (supported by the UK government for instance) is that the 60mg figure is not only unrealistic (the average daily intake in the UK is 48mg per day) but also unnecessary.
What they propose therefore, is that the recommended allowance be based on an intake known to keep a population fit, and to allow a safety margin on top of that. The UK recommended intake is therefore 30mg a day, designed to allow for individual variation and for the stresses of everyday life.
Why are patients given extra vitamin C before and after an operation?
We need vitamin C to help form scar tissue, so it's not surprising that we need extra doses on such occasions. Indeed, following any injury (whether it's a burn, a fracture or any operation) the levels of vitamin C in the body drop dramatically.
Because of this, anybody due to have a major operation needs a good supply, so it's common practice to give them doses of around 250mg per day for a few days before the operation and afterwards until the patient is back on his normal diet. Extra doses of vitamin C are often given to patients suffering from bed sores, too, because it assists the formation of collagen - and so scar tissue. There's absolutely no evidence, though, that larger doses speed up the usual recovery process.
What's the best way to get your vitamin C?
For practical purposes, the best way to get your vitamin C is from citrus fruits and juices. Fresh orange juice is best, followed by grapefruit, lemon and canned orange juice (at about 100mg per 8oz glass). Other juices such as apple, pineapple or grape are not so good, and tomato juice ranges from 30mg per glass to none at all. Guavas are also an excellent source.
Other rich sources include green peppers, while tomatoes (fresh or canned), all salad greens, fresh strawberries and raw cabbage average around 30 to 50mg per portion. Green vegetables such as spinach, Brussels sprouts and broccoli are also good sources, but you have to be careful you don't cook out all the goodness. Potatoes and peas only supply 20 to 30 mg per helping, but they're important because we eat them - especially potatoes - in such large quantities. Butter, cheese, eggs, bread, and dry beans are completely lacking in vitamin C, while milk and most meats contain a little. But liver and kidney are good sources.
Cooking losses can be minimized if vegetables are prepared just before cooking and then plunged into boiling water for the minimum amount of time. Using small amounts of cooking water will reduce losses of the vitamin due to leaching, since vitamin C is soluble in water; add the cooking water to gravy to retain any vitamins lost. Further vitamin C is lost if food is kept warm for some time before eating.
Losses of vitamin C also occur in storage as well as through wilting of leafy vegetables and bruising of fruit. Freshly dug potatoes contain 30mg vitamin C per 100g, but after nine months less than 25 per cent is left.
The vitamin C content of canned, bottled and frozen foods remains constant since air is excluded, although there is some vitamin loss during sterilization or blanching procedures prior to packaging. However, foods required for canning or freezing are harvested at peak condition, which usually means maximum vitamin C content. Consequently these foods often have a higher vitamin C content when eaten than so-called fresh fruit and vegetables which have been lying around in markets and shops for several days. It has also been shown that the vitamin C in fruit juices falls off once the containers are opened - 30 to 50 per cent is lost after eight days and as much as 90 per cent after a month.
What's the basis of the claim that extra doses of vitamin C can cure colds?
The idea of taking large doses of vitamin C as a preventive measure against the common cold - and other diseases - was the brainchild of Dr. Linus Pauling, twice winner of the Nobel prize (for work in other fields). His book on the subject was very widely read, and many people did - and do - take large amounts of vitamin C after reading it, much to the delight of the manufacturers of products rich in the vitamin. Pauling based his hypothesis on an analysis he did of the eating habits of Man as compared with his closest animal relatives. He calculated the average vitamin C content of 110 natural plant foods that a gorilla might eat, and showed that were a man to eat the same diet he would consume 2.3g of the vitamin. He also worked out how much vitamin C other animals (who do not require the vitamin in their diet as they make enough in their own bodies) were making for themselves each day. He came to the conclusion that man needed an intake of 10g of vitamin C every day something like 140 times the most generous recommended daily allowance to date.
He maintained that studies had shown that in this kind of dosage, vitamin C reduces the frequency and the severity of the symptoms of the common cold. Unfortunately, later attempts to repeat the same results in carefully controlled trials found these claims either exaggerated or impossible to reproduce. Because of this, the medical establishment felt unable to endorse his claim or recommend it to the public.
What does vitamin D do for you?
Your body needs vitamin D because it helps in the process of building strong and healthy bones. It's an important vitamin in everyone's diet, whatever their age, because bone never actually stops developing; there's a constant process of renewal as outer tissues are shed and new tissues form. It's especially important that young children get enough of this vitamin, as the presence of vitamin D helps to change soft, malleable bones into tougher, more resilient structures.
Vitamin D is popularly known as the 'sunshine' vitamin - for ultraviolet light is an important source. When the sun shines on your skin, the ultraviolet rays convert the natural fats beneath the skin surface into vitamin D.
Certain foods also provide you with the vitamin, though. Dietary vitamin D becomes important during the winter months after your body has used up any reserves which have formed in the skin.
Vitamin D is found most plentifully in cod liver oil and halibut liver oil as well as in fatty fish, such as sardines and kippers. There are very small amounts of vitamin D in summer butter and milk, margarine, cheese and egg yolk, too.
Doctors often recommend that during pregnancy, women should take extra amounts of vitamin D to help metabolize larger amounts of calcium, and so meet the needs of the growing baby in the womb. The normal shedding and renewal of a woman's bone tissue at this time is affected by certain hormonal changes. These changes, which speed up the rate at which bone tissue is shed and slow down renewal, allow the baby to take the calcium it needs, but may leave the mother short.
This is unlikely to happen to the mother who has a wellbalanced diet. But it is of importance to the woman who is already suffering from osteomalacia or for those who have to remain indoors for much of their pregnancy.
It is possible that some individuals may suffer allergic reactions from the use of various dietary supplements or the media in which they are contained; if such reactions occur, consult your doctor. The author and publisher assume no responsibility.
The Whole Health Manual, Patrick Holford, Lothian Publishing Company, 1983.
Nutrition Book, Jeni Edgley, Lansdowne Press, 1985.
The Macquarie Home Guide to Health and Medicine. 1991.
Reference Daily Intake retrieved March 23, 2010 from http://en.wikipedia.org/wiki/Reference_Daily_Intake
Avitaminosis retrieved March 23, 2010 from http://en.wikipedia.org/wiki/Avitaminosis