The Pharmaceutical Journal Vol 267 No 7179 p911-936
22-29 December 2001

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Christmas miscellany summary

Nutrition — all our yesterdays

We are all being encouraged to eat more fruit and vegetables and to restrict our fat intake following evidence emerging of the link between diet and disease. Intriguingly this advice is not new. John Kellogg in the 19th century advocated a high fibre diet rich in fruit and vegetables.

This article compares a typed diet sheet given to two women customers of a health food shop in Crewe in 1937 with current recommendations. The women were my grandmother, who was frequently ill and had recently had a kidney removed, and my mother, who did not seem to have the energy of her sister (and in retrospect probably had childhood asthma). The diet therefore was to improve their general health. My mother remembers that it particularly benefited her father who lost weight and had lots of energy. She remembers lots of fruit, unusual at the time, and unprocessed cereals — the rice pudding made with brown rice was a memorable failure.

Old and new compared

The 1937 diet sheet is concerned with a holistic approach — "Life lived in harmony with nature means health, only when one is out of tune on the physical, mental or spiritual plane, is there disease." This approach is one which is familiar to alternative practitioners and, increasingly, doctors are being encouraged to treat the whole person. Nutrition is blamed for many illnesses — "... the rising figures for diabetes, cancer, rheumatism and other troubles are all indicative of faulty nutrition." It is not clear how this philosophy was developed but certainly the link between diet and disease is now accepted for many of the major diseases of the western world.

The dietary solution offered in 1937 also sounds familiar today. The recommended diet is high in fruit and vegetables, low in salt and fat and relatively low in protein, especially red meat. Table 1 compares the 1937 diet with modern recommendations for a diet to reduce the risk of cancer.¹

There are also modern dietary recommendations to reduce the risk of cardiovascular diseases and osteoporosis. In common with the recommendations to reduce the risk of cancer, an increased use of fruit and vegetables and a reduced use of salt is recommended to reduce the risk of cardiovascular disease. Further recommendations call for an increased intake of oily fish.

This is not specifically mentioned in the 1937 diet although herring is given as a good protein food. A reduction in the intake of saturated fats is also an important recommendation to reduce cardiovascular disease risk and these should be replaced by polyunsaturated or monounsaturated fats. The 1937 diet does not discuss saturated and unsaturated fats but it does state that "the best form of fat is vegetable in origin".

The Committee on Medical Aspects of Food and Nutrition Policy (COMA) gave advice on bone health in 1998. It stated that an adequate vitamin D status could be achieved from exposure of the skin to summer sunlight although it mentioned the need to balance this with the increasing risk of skin cancer. It also stated that dietary means should be used to ensure adequate calcium intakes.

The 1937 diet does not mention bone health, there was probably less awareness of osteoporosis then; however, it does recommend sunlight for the production of vitamin D.

Diet and disease

Meat and proteins The rationale behind the 1937 diet is not entirely consistent with modern thinking.

The reasons for restricting meat intake were given in 1937 as follows: "In taking protein foods of animal origin it is well to remember that just as we have body waste and ills, so have animals, and at the time of death, often in a condition of fear and agitation on the animal's part, all these waste products are left in suspension in all parts of the body, right down to the smallest cell. Therefore one has to deal not only with one's own wastes but also with the waste matter present in the protein foods, a burden which is often beyond certain types of people."

Current thinking is that heterocyclic amines, which have been shown to be carcinogens in the mammary gland and colon of rodents, are formed on the surface of meat when it is cooked by grilling, roasting, frying and barbecuing. Individuals who are "fast acetylators" in their metabolism of these compounds are at an increased risk of developing polyps and large bowel cancer. Meat also increases the amount of residue entering the large bowel and affects the by-products formed by colonic flora. With high meat diets, the amount of N-nitroso compounds produced is high and these may be involved in the development of cancer.

Whatever the rationale, a high meat intake is associated with an increased risk of bowel, breast, prostate and pancreatic cancer. In addition since meat is a source of saturated fats a high meat intake would make the recommendation to substitute saturated fats with mono and polyunsaturated fats for the prevention of cardiovascular disease difficult to achieve.

The 1937 diet sheet recommends pulses as a good source of protein and the soya bean gets a special mention: "The soya bean is an example of a protein food with an alkaline ash." Soya is now known to contain isoflavenoids and lignins which are converted by intestinal bacteria to hormone-like compounds with weak oestrogenic and antioxidative activity. Evidence is emerging that these compounds may offer protection against a wide range of human conditions, including breast, bowel, prostate, and other cancers, cardiovascular disease, brain function, osteoporosis and menopausal symptoms.

The 1937 diet recommends a limited amount of protein and states that "too much protein means toxaemia". Certainly too much red meat is now thought to be a risk factor for cancer and McCarty in a recent article² states: "An unnecessarily high intake of essential amino acids — either in the absolute sense or relative to total dietary protein — may prove to be as grave a risk factor for 'Western' degenerative diseases as is excessive fat intake."

Fruit and vegetables The need for the high levels of fruit and vegetables is given in the 1937 diet sheet as follows: "These are foods that provide the body with ample bulk, roughage, organic mineral salts, vitamins, pure soft water and above all the end product of digestion is an alkaline ash. These foods are thus base forming, alkaline products that tend to counterbalance the acidity of other groups and maintain the bloodstream in perfect condition".

Dietary fibre is still thought to be important in the prevention of disease. It is one of the factors proposed to account for the differences in the rates of colorectal cancer between Africa and westernised countries, on the basis that increased dietary fibre may increase faecal bulk and reduce transit time. Constipation is known from case-control studies to be a risk factor for colorectal cancer.

Antioxidants in fruit and vegetables may suppress spontaneous mutation and certainly a low intake of fruit and vegetables is linked to cancers of the breast, lung, bowel, prostate, stomach, oesophagus, pancreas, and uterus. An increased consumption of fruit and vegetables has also been shown to reduce blood pressure and cardiovascular disease risk. In addition moderately elevated homocysteine levels may be associated with stroke and are associated with a deficiency of dietary intake of folate, vitamin B₆ and vitamin B₁₂ .

Fats The rationale behind limiting fat intake given in the 1937 diet sheet was that fats are "heat foods with an acid ash. Too much means digestive trouble, disordered liver etc." Today, although fats are not convincingly linked to cancer, a high fat diet will contribute to obesity, and obesity is associated with an increased risk of endometrial, breast, and to some extent bowel cancer, so that a diet with limited fat intake is appropriate to reduce cancer risk.

Obesity of course is also associated with other diseases such as diabetes and cardiovascular disease. A high fat intake is associated with disturbances of glucose metabolism, type 2 diabetes and impaired glucose tolerance and in this respect it is a high fat diet containing a high proportion of saturated fats that appears to be particularly deleterious. Reducing total intake of saturated fat and replacing it with polyunsaturated or monounsaturated fats is known to reduce cardiovascular disease risk.

Cereals The 1937 diet sheet advocates wholegrain foods and states: "Wheat, for example, has the germ, with its vital vitamin E, removed, then the roughage and mineral salts disappear as the husk is stripped away, the resulting flour is still not pure white, so that is bleached with a chemical and then this product is ready for sale."

Unprocessed cereals are a source of non-starch polysaccaride and a low intake of non-starch polysaccharide is now known to be associated with cancer of the breast, bowel, and pancreas. Wholegrain cereals are also a source of lignins, which act at weak oestrogens and may be cancer protective, although lignins have been less well investigated than the isoflavones found in soya. There is also a suggestion that substituting whole for refined grain products may reduce the risk of diabetes mellitus.

Salt A statement that salt is used to excess is given in the 1937 diet sheet, although there is no specific reason given for this belief. We now know that using less salt when preparing food and the elimination of excessively salty food from the diet reduces blood pressure and therefore lowers the risk of cardiovascular disease.

Conclusion

The 1937 diet recommendations are remarkably similar to the advice given today. The diet would have been thought to be unusual at that time when meat and dairy products were generally thought to be important to health. Also the range of vegetable oils and the wide variety of fruit and vegetables which we enjoy today were less readily available.

The real problem then, as now, is that a change in lifestyle is difficult for a whole variety of reasons. The final quote that my mother and grandmother had to digest, is also suitable as a lovely Christmas message: "These things all seem so simple, but one of the real difficulties of people is to overcome the habits of years, to believe, the old, yet ever new teaching, the value of water, air, sun, light, exercise, simple unspoilt natural foods, love in place of hate, trust in place of distrust, hope in place of hopelessness, calm in place of fret."