Vitamins - what do they do?

Reviewed by Dr Dan Rutherford, GP
Recommended daily amounts (RDAs)Throughout this factsheet, recommended daily amount refers to the European Union recommended daily amounts (EU/RDA) for nutritional labelling of food products. Nutritional requirements are often slightly different for young children and adolescents, and during pregnancy and breastfeeding. Ask your doctor or pharmacist if you are concerned about your own or your children's vitamin intake.
Vitamin A (retinol) propertiesGood for:
eyesight
growth
appetite and taste.Signs of vitamin A deficiency:
night-blindness.Good sources of vitamin A:
liver
fish-liver oil
carrots
green leafy vegetables
egg yolks
enriched margarine
milk products
yellow fruits.Recommended daily amount: 800 micrograms.
Poisoning: vitamin A is a fat-soluble vitamin and so it is stored for a long time in the human body, especially in pregnancy. An overdose may be dangerous. Destroyed by: fatty acids.
Vitamin B1 (thiamine) properties Good for:
nervous system
digestion
muscles
the heart
alcohol-damaged nervous tissues.Signs of vitamin B1 deficiency:
tingling in fingers and toes
confusion
difficulties in maintaining balance
loss of appetite
exhaustion
weakened powers of concentration. Good sources of vitamin B1:
liver
yeast
rice
wholemeal products
peanuts
pork
milk.Recommended daily amount: 1.4mg.Poisoning: no poisoning dangers as the vitamin dissolves in water, so excess is excreted in the urine. Destroyed by: high temperatures, alcohol and coffee.
Vitamin B2 (riboflavin) properties Good for:
growth
skin
nails
hair
sensitive lips and tongue
eyesight
protein, fat and carbohydrate breakdown. Signs of vitamin B2 deficiency:
itching and irritation of the eyes
itching mucous membranes
itching lips and skin. Good sources of vitamin B2:
milk
liver
yeast
cheese
green leafy vegetables
fish.Recommended daily amount: 1.6mg.Poisoning: no danger of poisoning as the vitamin dissolves in water, so excess is excreted in the urine.Destroyed by: light (this is why milk-cartons are better than bottles) and alcohol.
Vitamin B6 (pyridoxine) properties Good for:
preventing skin conditions
nerve problems
helping the body absorb proteins and carbohydrates.Signs of vitamin B6 deficiency: skin inflammation.Good sources of vitamin B6:
fish
bananas
chicken
pork
whole grains
dried beans.Recommended daily amount: 2mg. Women taking the contraceptive pill may need more. Poisoning: may cause nerve problems in large doses, but current evidence is conflicting about the maximum safe dose. Discuss this with your pharmacist if you are concerned. Destroyed by: the contraceptive pill, roasted or boiled food, alcohol and oestrogen (the female hormone).
Vitamin B12 (cobalamin) properties Good for:
making red blood cells
the formation of the nerves. Signs of vitamin B12 deficiency:
tiredness due to anaemia
abnormalities of nervous tissue function.Good sources of vitamin B12:
fish
liver
beef
pork
milk
cheese. Vitamin B12 deficiency can arise in strict vegans because our dietary sources of vitamin B12 are animal in origin. The other main cause of vitamin B12 deficiency is pernicious anaemia.Recommended daily amount: 1 microgram. Poisoning: no danger as the vitamin dissolves in water, so excess is excreted in the urine. Destroyed by: water, sunlight, alcohol, oestrogen and sleeping pills.
Vitamin C (ascorbic acid) properties Good for:
the immune defence system
protection from viruses and bacteria
healing wounds
reducing cholesterol content of the blood
a natural laxative
cell lifespan
preventing scurvy. Signs of vitamin C deficiency:
tiredness
bleeding gums
slow-healing wounds. Good sources of vitamin C:
citrus fruits - especially kiwi fruit
berries
tomatoes
cauliflower
potatoes
green leafy vegetables
peppers.Recommended daily amount: 60mg. Poisoning: Large doses can cause diarrhoea and nausea. Some scientists have recently argued that 1 to 5g per day may influence your genes. Destroyed by: boiling food, light, smoking and heat.
Vitamin D propertiesGood for:
strong bones and teeth.Signs of vitamin D deficiency:
unhealthy teeth
osteomalacia (causes weakening of bones)
rickets in children.Good sources of vitamin D:
cod-liver oil
sardines
herring
salmon
tuna
milk and milk products
sunlight (the action of sunlight on the skin allows our bodies to manufacture vitamin D).Recommended daily amount: 5 micrograms.Poisoning: this vitamin is fat-soluble so can accumulate in the body and overdoses are dangerous. Destroyed by: mineral oil.
Vitamin E (tocopherol) properties Good for:
fighting poisons - vitamin E is a powerful 'anti-oxidant'.Signs of vitamin E deficiency:
weak muscles
fertility problems. Good sources of vitamin E:
nuts
soya beans
vegetable oil
broccoli
sprouts
spinach
wholemeal products
eggs.Recommended daily dose: 10mgPoisoning: there is a theoretical but slight risk of overdose, as vitamin E is fat soluble. Destroyed by: heat, oxygen, frost, iron, chlorine and mineral oil.
Folic acid properties Good for:
production of red blood cells
essential during the first three months of pregnancy to prevent birth defects such as spina bifida, cleft palate or cleft lip. Signs of folic acid deficiency: anaemia, red tongue.Good sources of folic acid:
carrots
yeast
liver
egg yolks
melon
apricots
pumpkin
avocado
beans
rye and whole wheat
green leafy vegetables.Recommended daily amount: 200 micrograms. Pregnant women and women planning a pregnancy should take a daily supplement of 400 micrograms, continued for the first 12 weeks of pregnancy.Poisoning: no danger of poisoning as it dissolves in water, so excess is excreted in the urine.Destroyed by: water, sunlight, oestrogen, heat.
Based on a text by Dr Carl J Brandt

Vitamins

Reviewed by Dr Dan Rutherford, GP
What are vitamins? The term 'vitamin' is derived from 'vital amine'. They are a group of substances required in small amounts for growth and development but which cannot be manufactured by the body.Without vitamins the human body would not survive. We all need vitamins in order to live a long and healthy life. Most of us get sufficient quantities of vitamins from our food, but it may be necessary for some people to take a vitamin supplement (eg pregnant women and the elderly).
How easy is it to get all the vitamins we need from our diet? A varied diet is essential if we are to obtain the nutrients we need. However, this is not always easy: fruit and vegetables age (an apple in a bowl loses vitamins hour by hour) and deep frozen products may often contain more vitamins than vegetables stored for a long time at room temperature. Therefore, it is especially important to eat a wide variety of fresh foods.Too little of just one vitamin may disturb the body's balance and cause health problems. But taking too many vitamins can also be dangerous. This is especially true of the fat-soluble vitamins A, D, E and K: it is harder to get rid of excess of these vitamins through urine - the most common way for us to eliminate body waste products.
Which vitamins do we know about?New vitamins are discovered occasionally, but presently we know of the following vitamins: A, B1, B2, B3, B5, B6, B10, B11, B12, B13, B15, B17, C, D, E, F, G, H, K, L, M, P, T and U.
Where do vitamin supplements come from?Most vitamin supplements have been extracted from natural foods. For instance, vitamin A comes from fish-liver oil. Vitamin B comes from yeast or liver. Vitamin C is often extracted from small berries in roses, and vitamin E is extracted from soy beans or maize. Vitamins may also be synthetically manufactured, but synthetic vitamins are not always as effective as their naturally-derived equivalent.
How should vitamins be stored?It is important to keep vitamins in a dark, cool place, or they will 'go off', just like apples in a bowl. The best place to store vitamins is in the refrigerator - make sure there is a lid on the container. A few grains of rice in the container will prevent moisture getting into the tablets.
When should you take vitamin supplements?The best time to take vitamins is during the day, after a meal. Never take vitamins on an empty stomach - they will quickly passed out in your urine. This is especially true for the B and C vitamins that dissolve in water. The fat-soluble vitamins A, D, E and K can be stored in the body for up to 24 hours and can sometimes be stored in the liver for even longer.
Are vitamins and minerals the same thing?Vitamins and minerals are two completely different things: minerals help the vitamins work. The 10 most important minerals are: calcium, iodine, iron, magnesium, phosphorus, copper, manganese, chromium, selenium and zinc. There is a specific recommended daily allowance for each of these, as well as for each of the vitamins. Based on a text by Dr Carl J Brandt, GP

Heartburn

Written by Dr Dan Rutherford, GP and Ove Schaffalitzky de Muckadell, consultant and professor of internal medicine
Heartburn occurs when the acid contents of the stomach pass backwards up into the food pipe (called the gullet or oesophagus). This is also known as stomach acid reflux. Most people have stomach acid reflux at some point in their lives, either as heartburn or acid regurgitation.
What causes heartburn? Heartburn typically occurs after eating a large meal or drinking a lot of alcohol. Some people get heartburn when they bend over or lie down. The frequency of stomach acid reflux varies from one person to another. For most people, it happens very rarely. But weekly or daily incidents of heartburn or acid regurgitation may occur.
Is heartburn dangerous? Heartburn is annoying and may have a detrimental effect on a person's wellbeing. Sometimes the tendency for heartburn may develop into a mucous membrane inflammation in the food pipe, also known as oesophagitis. In the worst cases, oesophagitis may become complicated with ulcers, which, in rare cases, may bleed or cause chronic anaemia. Occasionally, reflux oesophagitis may become complicated if scars cause a tightening or narrowing (stricture) in the food pipe. A gullet stricture can prevent swallowing. This is a serious condition, which requires immediate examination and treatment.
How does gastric acid end up in the food pipe? At the lowest part of the food pipe there is a ring of muscle (sphincter) where it passes through a hole in the diaphragm.
The diaphragm
The diaphragm is a thin sheet of muscle dividing the lungs from the stomach.
The diaphragm holds the gullet sphincter in place and the system works as a one-way valve.If the one-way valve does not function properly, acid from the stomach (gastric acid) will be able to pass up into the food pipe. This tendency increases if:
the stomach contains large amounts of food or fluids (especially if the food is fatty, the drink alcoholic)
there is something pressing on the stomach, eg such as occurs when people are overweight.
What increases the risk of heartburn? There is often no known reason for increases in heartburn. But occasionally one of the factors below may contribute.
Hiatus hernia
Other risks
Chocolate, peppermint, coffee and alcohol hamper sphincter function.
Tobacco hampers the function of the sphincter.
Constipation increases the chance of acid reflux.
This is the name for the condition where the upper part of the stomach has passed up through the hole in the diaphragm. This means the muscle fibres of the sphincter can't press on the lower part of the food pipe. As a result, the lower part of the gullet is normally open, when it should be closed.
ObesityIn people who are overweight, the fat in their abdominal cavity exerts more pressure on the stomach. This causes high pressure inside the stomach, and the contents of the stomach may then be pushed up into the food pipe. Weight loss will reduce the chance of stomach acid reflux.
PregnancyThe enlarged uterus (womb) presses on the stomach. This causes the same kind of high pressure inside the stomach as in people who are overweight. The change that pregnancy brings to the balance of the hormones also leads to a general relaxation of the gullet sphincter.
Large meal portionsThe risk of stomach acid reflux increases with more food in the stomach. The risk will be greater after large (and especially fatty) meals, where the food is in the stomach for a long time before it passes on to the intestines. If you avoid eating more than is necessary, the risk of stomach acid reflux is reduced.
Lying downIf you lie down, the chance of stomach acid reflux increases due to gravity. You can avoid this to some extent by raising the head-end of your bed (see tips below).
What can I do to help myself?
If you are overweight, try to lose a few pounds.
Avoid large fatty meals and try not to eat just before bedtime.
Try to cut down on coffee.
Avoid drinking too much alcohol.
Quit smoking.
If suffering from nightly symptoms, try using an extra pillow or putting a couple of books under the legs at the head of the bed.
If heartburn or acid regurgitations are rare (less than five times a month) medicines bought from a chemist such as antacids can be used.
What medicines treat heartburn?
Antacids Since heartburn is caused by acid from the stomach, one of the simplest ways to relieve the discomfort is to neutralise the acid with an antacid. Antacids usually contain a mixture of magnesium and aluminium salts, calcium carbonate or sodium bicarbonate. Those containing high amounts of sodium may not be suitable for pregnant women or those on a sodium restricted diet, such as people with high blood pressure or heart disease. Antacids are available as tablets that can be sucked or chewed and liquids. The choice is down to personal preference, but liquids may work faster and tablets may have a longer lasting effect. Antacids can reduce the absorption of certain other medicines from the gut, so if you are taking any other medicines you should always check with your pharmacist before taking an antacid at the same time.
AlginatesSome antacid products, eg Gaviscon, also contain sodium alginate. Sodium alginate is a substance that forms a ‘raft’ that floats on top of the stomach contents. The raft prevents stomach acid from passing back into the food pipe and protects the food pipe from the acid. Products containing alginates are particularly useful for heartburn caused by pressure on the stomach, such as during pregnancy. They are also available as tablets and liquid.
H2 antagonistsH2 antagonists include medicines such as cimetidine, ranitidine, nizatadine and famotidine. All of these can now be bought from pharmacies by adults over 16 years of age. They work by blocking histamine receptors in the stomach, which prevent the cells in the stomach from producing too much acid. This type of medicine may not be suitable for people with liver or kidney problems. They should only be used for a maximum of two weeks without consulting your doctor. Cimetidine has the potential to interact with various medicines, both bought and prescribed, so you should always check with your pharmacist before taking it with any of your existing medicines.
When should I consult my doctor? If heartburn or acid regurgitation occurs often, or the symptoms are very annoying, consult your doctor. You should also consult a doctor if you:
have trouble swallowing
are middle-aged or older and have new symptoms
have suddenly lost a lot of weight.Your doctor will decide whether a further examination or more effective medicine is needed.

Constipation

Reviewed by Dr Dan Rutherford, GP
Stomach pain is a common symptom of constipation.
What is constipation?Although constipation is a common term, from a medical perspective it is hard to define precisely. The dictionary definition is: ‘A condition in which bowel emptying occurs infrequently or in which the stools are hard and small or where bowel movement causes difficulty or pain.’ But defining infrequent is difficult when some 90 per cent of people in Western countries have a bowel pattern that ranges from three bowel movements a day to three per week. And it is possible to move your bowels every day and still be constipated if the stools are hard and difficult to pass. Equally, a daily bowel movement is by no means essential for, nor a sign of, good health. Provided the bowels move regularly and without discomfort, it doesn't matter if your natural bowel frequency is once every two or three days.
How common is it?Constipation is thought to affect a quarter of the population at some time. Constipation is more common in the elderly because:
the power of the bowel muscles diminishes with age
they tend to take more medicines that have constipating side effects.
Bypass diarrhoea
This happens when a hard plug of stool in the lower bowel (faecal impaction) stops a proper evacuation.
Only the more liquid stool from higher up in the bowel can then be passed.
For this reason correct diagnosis is important.
Medicine to slow the bowel down will make the condition worse if a person is actually constipated.
What are the symptoms of constipation?
Tummy pain associated with bowel movements.
A feeling of incomplete emptying of the bowel.
A bloated feeling in the stomach region.
Diarrhoea: constipation is one of the most common causes of diarrhoea, especially in the elderly in care. Diarrhoea caused by constipation is known as bypass diarrhoea.
What causes constipation?
Poor general health.
Immobility or an inactive lifestyle.
Insufficient fluid intake.
A diet low in fibre. Fibre retains fluid and makes the stools light and soft.
Irritable bowel syndrome (IBS).
Inadequate toilet facilities.
An underactive thyroid gland.
Spinal injury.
Multiple sclerosis.
Colon or rectal cancer.
Kidney failure.
Too much calcium in the blood.
Tumours and other lesions of the bowel.
Certain medicines, eg codeine-containing painkillers (co-dydramol, co-proxamol), morphine-like painkillers, antidepressants, aluminium-containing antacids, iron supplements, and anticholinergics such as procyclidine (used in Parkinson's disease).Constipation should not simply be accepted or ignored. Persistent constipation or any change in bowel habit (whether towards constipation or looseness) should be investigated, especially in adults over 40 years. However, for most people with long-standing constipation there is no identifiable cause.
What can help prevent constipation?
A well-balanced diet high in fibre, including bran, fruits and vegetables, is often helpful.
Cutting down on white bread, cakes and sugar.
Drinking at least 8 to 10 glasses of water a day. Hot beverages, such as coffee, tea or hot water may stimulate bowel movements.
Prunes and plum juice can also be beneficial.
Regular exercise improves digestion and reduces stress.
A regular bowel habit. The best time is usually the first hour after breakfast. Don't hurry and sit for at least 10 minutes, regardless of whether you manage to pass a stool. Don't strain.
What are the complications of constipation?
Haemorrhoids. These are swollen veins at the anus, caused by straining at a stool over a long period of time. If large enough they will be visible from the outside. They can be painful or cause local bleeding.
Dependency on laxatives. The bowel in someone who has abused laxatives over a long period of time becomes sluggish and eventually dependent on the use of these drugs.
Hernia (bulging of the abdominal contents through a weak point in the abdominal wall). This is made worse by too much straining when trying to get rid of hard stools.
A prolapse of the womb or rectum. These complications result from excess straining and weakness of the muscles in this area.
What medicines are used to treat constipation?
Bulking agents such as bran and ispaghula husk. These work gently and are the most common type of laxatives (examples are Fybogel and Regulan). They don’t need to be in the form of medicines – increasing the fibre content of your diet should be the main treatment. Bulking agents should always be taken with plenty of fluids.
Stimulant laxatives that cause the bowel muscles to contract such as senna or bisacodyl.
Osmotic laxatives (such as lactulose) that increase the amount of water in the stools by drawing water in from the bowel lining.
Detergents that break down surface layers in the stool, letting water penetrate and soften it (eg docusate).
Macrogols (polyethylene glycols). These are administered along with extra fluids, so they don't draw more water into the bowel from the body. Examples are Idrolax and Movicol. Macrogols may be of long-term benefit to patients with persistent constipation and faecal impaction.
Which treatment is best?
Laxatives
Large amounts of laxatives are bought over the counter every day.
This is due in part to the belief that it's desirable to move the bowels daily.
Laxatives of all types are among the most commonly prescribed medicines.
Yet little detailed medical research has been done to work out the best ways of treating constipation.
There are many different combination laxatives available both on prescription and over the counter. None of these laxatives is superior to any other, and in most people the choice is an individual one. Sometimes, a medicine prescribed for a separate condition may have constipating side effects. Changing this medicine will be all that's required to get rid of the constipation. Someone who has had a period of immobility will probably find their constipation improves once they are up and about again. References Kamm MA. Constipation and its management. British Medical Journal 2003;327:460-462. http://bmj.com/cgi/content/full/327/7413/459 Tramonte SM, et al. The treatment of chronic constipation: a systematic review. Journal of General Internal Medicine 1997 12: 15-24. Summary at http://www.jr2.ox.ac.uk/bandolier/band46/b46-3.html Based on a text by Dr Torben Nathan, Dr Carl J Brandt and Dr Ove Schaffalitzky de Muckadell, professor of Internal Medicine