The importance of nutrition

Neglecting nutrition has a price

If you believe that we are indeed what we eat, don't you find it surprising that in the medical curriculum learning about nutrition is conspicuous by its absence? We are so keen to medicalise everything that we often ignore the fact that the patient in front of us is a whole person not just a sick bit. Everything they do, including what they do or don't eat or drink, will affect their health.¹

Take the following typical scenarios: a teenage girl who is tired all the time, a middle aged man with chronic headaches, and an elderly woman with a venous ulcer that will not heal. How many of you would rush in with a monospot test suspecting glandular fever, refer for computed tomography to rule out a tumour, or apply a topical antibiotic after screening for diabetes, assuming that the skin breakdown is due to a secondary bacterial infection?

All these things may not be wrong in themselves, but take a moment to ask them about their diet. You will then discover that the teenage girl is going through a vegetarian phase but has not read up about her added nutritional requirements. Having to cook for herself, she is living on a diet of baked beans, chips, and frozen vegetarian pizzas and is not getting the B vitamins she requires. The middle aged man eats cheese sandwiches followed by a chocolate bar for his packed lunch everyday and daily drinks at least four cups of coffee. His headaches disappear once he replaces the cheese with ham, the chocolate bar for a muesli one, and switches to decaffeinated coffee or tea.

As for the elderly woman, she has been living on a toast and jam diet and is not getting any of the vitamins and minerals, notably vitamin C and zinc, so vital for wound repair.

Many different diseases and illnesses are linked to diet in some way. The most obvious is coronary heart disease and diabetes where a diet high in saturated fats is a causal factor. There is also strong evidence on the link between folic acid deficiency and neural tube defects² and calcium and vitamin D deficiency resulting in reduced bone mass which can lead to osteoporosis.³ There are many other areas where the diet is thought to have a role, but there is still some debate on, for example, fibre and bowel cancer and omega three oils and arthritis. Food allergies also have a huge impact on health, peanut allergy being one of the most common.⁴ In the past few months alone the BMJ has published papers on probiotic milk decreasing infections in children,⁵ cranberry juice reducing the recurrence of urinary tract infections in women,⁶ and zinc supplements reducing the incidence of diarrhoeal episodes but not malaria in African children.⁷

If you go to a developing country for your elective you will see a wide variety of nutritional deficiencies. For example, vitamin A deficiency causing blindness, iodine deficiency causing endemic goitre, and the tragedy of marasmus and protein energy malnutrition. Then there is pellagra.

The association between pellagra and niacin deficiency was discovered by Goldberger, an American epidemiologist at the beginning of the 20th century. Pellagra is characterised by the three Ds—dementia, dermatitis, and diarrhoea—and at that time affected 50 000 and killed 7000 Americans a year. Because it was only the poor living in squalid conditions in the deep south who were affected, the common belief was that it was an infection of some sort.8 Goldberger, however, believed that it was caused by some sort of vitamin deficiency as the staple diet was cornbread, fat meat, and black molasses. He distributed yeast to the poor communities with dramatic effects. We now know that the vitamin in question was niacin and most common breakfast cereals are now fortified with it. However, don't write it off as a disease of the past, or of those in developing countries (particularly Latin America where the staple diet is corn based). It is something to remember in vegans and those with gluten intolerance.

I hope that I have managed to convince you that nutrition is too important a subject to be ignored or be relegated to the interested few in a special study module. Just in case, the studentBMJ has commissioned a series of articles focusing on various aspects of nutrition. In this month's article, nutritional scientist Sarah Schenker discusses the truth behind fad diets (p 318). If we all remembered our physiology better we would not be taken in by the latest "miracle" diets. Yet another reason why a basic knowledge of nutrition is so important.

1. Weil A, Rees L. Integrated medicine. BMJ 2001; 322:119­20.
2. Wise J. Neural tube defects decline in the US after folic acid is added to flour. BMJ 2001:322:1510.
3. Cadogan J, Eastell R, Jones N, Barker M. Milk intake and mineral acquisi­ tion in adolescent girls: randomised controlled intervention trial. BMJ 1997;315:1255­60.
4. Armstrong D, Rylance G. Nut allergy in children. Arch Dis Child 2000;82:422­8.
5. Hatakka K, Savilahti E, Pˆnk‰ A, Meurman JH, Poussa T, N‰se L, et al. Effect of long term consumption of probiotic milk on infections in chil­ dren attending day care centres: double blind randomised trial. BMJ 2001;322:1327­9.
6. Kontiokari T, Sundqvist K, Nuutinen M, Pokka T, Koskela M, Uhari M, et al. Randomised trial of cranberry­ligonberry juice and lactobacillus GG drink for the protection of urinary tract infections in women. BMJ 2001;322:1571­3.
7. M¸ller O, Becher H, Baltussen van Zweeden A, Ye T, Diallo DA, Konate AT, et al. Effect of zinc supplementation on malaria and other causes of morbidity in West African children: randomised double blind placebo controlled trial. BMJ 2001; 322:1567­70.
8. Middleton J. The blues and pellagra: a public health detective story. BMJ 1999; 319:1209.