Nutrition and Health

The effects on the biochemistry and physiology of the human body of diets differing only in the ratio of the two major carbohydrates, starch and sugars are discussed and related to the epidemiology of coronary heart disease and diabetes. Much of the evidence for causes of disease comes originally from epidemiology, where comparison is made between groups of people where the disease is common and groups where the disease is uncommon. But final determination of cause almost always depends on the result of experiment, with animals in the laboratory or with human volunteers.

Idiopathic renal stone comprises more than SO per cent of kidney stone disease. Whilst the incidence rate in the Western World is high, that in Africa south of the Sahara is very low. Epidemiological studies point to a dietary aetiology as the basis for stone formation in the kidney.

A number of dietary constituents increase the urinary risk factors for stone formation and one of these is sucrose. The sucrose effect is exaggerated when it is consumed in certain forms. There is also the evidence that a third of a normal population responds in an exaggerated manner in respect of an increased excretion of urinary risk factors when sucrose is consumed and this phenomenon has been noted in over 70 per cent of idiopathic stone formers. In studying the mechanism of this, insulin was found to influence distal renal tubular function to increased calcium excretion. Stone formers with an exaggerated urinary risk factor response to sucrose were found to have abnormally high and sustained blood levels of insulin following a standard glucose test meal. Where sucrose or sucrose products are in abundance, quite apart from its effect in increasing urinary risk factors in the population in general, there is particular vulnerability of a significant sub group within the population with this type of insulin response. Sucrose furthermore is known to induce nephrocalcinosis in the kidney of the rodent and similar calcific lesions have been found in the kidney substance of man and these have been observed to begin to appear within the first decade of life. Sucrose has also been observed in man to increase the excretion rate of an enzyme which is identified with renal tubular cell damage.

In order to investigate the relationships between diet and tooth decay the authors recently completed the first longitudinal study of diet and dental caries increment in children. 405 children initially aged 11.5 years each recorded their intake of foods and drinks for a total of 15 days over a period of 2 years. This is a review of some of the findings.

The evidence implicating consumption of sugars in the causation of dental caries is both diverse and overwhelming (Rugg-Gunn, 1983). Of the 30 or so observational studies relating diet and dental caries in children, all except one have been cross-sectional in design. Such a design is unsatisfactory in older children at least because there is little reason why a lifetime's caries experience should be related to a single estimate of dietary intake. In addition there have been few reports of the food intake in general, and sugars intake in particular, of children in the UK. A longitudinal survey of intake could indicate how choice of foods changes with age and if repeated could show how preferences change over time. The National Food Survey has provided some information on food acquisition (not consumption) over the past 40 years (Derry and Buss, 1984). Unfortunately, besides not estimating consumption this survey does not include foods bought and consumed away from the home such as confectionery and soft drinks. Furthermore, this survey collects data by household and so information for age and sex specific groups is not available. Comments regarding sugars consumption amongst children must be derived from data collected from properly designed dietary surveys of defined groups of individuals. Such knowledge of what children eat is essential to the planning of effective health education campaigns.

In order to contribute to the understanding of the relationship between diet and caries in children and to contribute to health education a longitudinal study was undertaken which had the following aim: to rank some defined dietary factors either singly or in combination in the order in which they explain the dental caries increment of over 400 children.

Sucrose is unequivocally implicated in the cause of dental caries. Biochemical, microbiological, animal and human clinical and epidemiological evidence support a causal relationship. The risk of caries is related both to the amount and the frequency of intake of sucrose. The evidence that sucrose is important is that a) extracellular synthesis of polysaccharides by plaque bacteria is dependent on high concentration of sucrose. Without synthesis of polymers S. mutans cannot colonize the mouth in large numbers, b) studies on animals show a relationship between sucrose content of a food and its cariogenicity, c) there is a direct relationship between the quantity of sucrose consumed and caries in humans, d) the relationship between dietary sucrose and caries in humans approximates an S-shaped curve that rises more steeply when the sucrose-containing products are consumed frequently and when newly erupted teeth are present in young children and adolescents. Following the sharp rise, the curve flattens out. Sucrose is much more cariogenic than starch in humans. Reduction in sucrose consumption levels by half will benefit dental health and is unlikely to have any detrimental effects on health.

Close birth spacing increases the risk of miscarriage, congenital malformation and perinatal death because it does not give a mother time to recover from the nutritional depletion caused by the first pregnancy or time to recover a normal hormonal profile before the beginning of the next pregnancy. The placental vitamin pump causes maternal vitamin depletion. Nutritional deficits do more damage to reproduction around the time of conception than later during pregnancy. Vitamin and mineral deficiencies can cause not only direct damage to embryonic development but damage to both male and female germ cells resulting in new mutations before a conception. New mutations can cause pregnancy failure or maldevelopment of the embryo. The realisation that nutritional deficits can be mutagenic opened a new chapter in nutritional science. Some nutrients are antimutagenic and already act as such within the digestive tract, but foods contain many other antimutagenic substances. The juices of many fresh vegetables in particular are antimutagenic.

The association between the organic movement and ‘alternative medicine’ may have been one reason for the failure of the McCarrison Society in Britain to appeal to many National Health Service doctors and dentists. This is unfortunate because the aims of the McCarrison Society have nothing to do with any system of medical care. Our hope is to prevent disease by promoting McCarrison's teaching that man is perfectly adapted to his food supply as it occurs in nature and that the greatest single cause of the diseases of industrial peoples is their dependence on foods made worthless or harmful by processing and refining.

This teaching applies to the modern epidemic of coronary heart disease. The evidence incriminating natural unprocessed fat as a cause of this disease is unconvincing.

A major task confronting those who establish calcium recommendations is the determination of a minimum level of calcium intake that will promote bone mineralization and/or reduce bone demineralization sufficiently to aid in the prevention of osteoporosis. The evidence reviewed here indicates that physical activity plays a primary role in the maintenance of skeletal integrity. Thus, to obtain data on calcium recommendations that are relevant to the general population, it is essential that calcium requirement studies use subjects whose physical activity profile is representative of the general population.

Of all the factors known to shift the [bone] remodeling process in favor of formation, perhaps the most important, after growth, is mechanical stress…

Heaney (1982)

The effects on the nitrate content of vegetables exposed to boiling in water for various lengths of time is described. Whilst certain cultivars show a steady decrease in nitrate levels, other varieties show an initial rise. The nitrate content of the cooking water used shows a sustained increase as the cooking time is extended.

The DHSS recently reported on school children's food intakes (1). Although the type of fat eaten is clearly an important issue, the DHSS study did not analyse the fat intake for its saturated and essential fatty acid content. We have explored the intakes of the children for fibre, sugar and saturated fats as well as additional vitamins and trace elements, not reported by the DHSS. The data from the DHSS survey was presented as a summary of the main food types eaten. They aggregated some food groups e.g. meat and meat products, fish and fish products, cakes and biscuits. While this approach might make little difference to protein intakes, it may be expected to make a difference to fat and essential fatty acid intakes. We have re-analyzed the childrens food intakes keeping within the confines of the food groups reported. We had to rely on certain assumptions about the nature of an ‘average’ diet; we therefore explored the possibility that our assumption of an average diet was incorrect and examined a worse and a better situation to define how much the nutrient intake varied. The result of the analyses illustrate an important principle in the context of the present concern for food and health. The only way in which we could satisfy NACNE and COMA recommendations for fat, saturated fat, fibre and sugar, without a radical change in eating habits, was by simply replacing half the ‘junk’ foods by an isocaloric amount of fresh fruit and vegetables. In addition there was a marked improvement in the intakes of beta-carotene, vitamin C, B6 and folic acid. These improvements in diet are of particular importance to children as it is well known that the period most vulnerable to nutritional distortions is during growth and development. No matter which way we looked at the data it is clear that not only are the school children's diets unsatisfactory from the view point of prevention of cardiovascular disease in later life but they also leave much to be desired from the view point of the wide range of nutrients known to be important for general health, growth and development. If this is true for the mean values obtained, it will be even more true for the ‘high risk groups’.

Inequalities in nutrition are associated with inequalities in health. Many surveys, mainly American, show that there are large variations between individuals in the quality and quantity of food consumed. Variations depend upon up-bringing, education, income and availability of food. In the United Kingdom there is a steep social-class gradient in age-specific death-rates for heart disease and other diseases including cancer. Of all the many possible nutritional factors the strongest inverse correlates with death-rates within the United Kingdom and in other developed countries are the consumption of fresh vegetables and fruit. Among the individual nutrients a low consumption of vitamin A, or its precursor carotene is associated with an increased cancer risk. Whole milk is a major source of vitamin A and carotene in the British diet and is also reported to be protective against osteoporosis and some forms of hypertension including preeclampsia. School meals can set a pattern of life-long eating habits.

Feeding rabbits with mycelium from Fusarium roseum is shown to produce infertility, the disappearance of aggressivity, and homosexual behaviour in males, while the effect of the females is only infertility. This mycelium contains the mycotoxin zearalenon which has effects similar to those of the female hormone. This fungus willingly grows uncommon crops and is consumed both by people and animals—although normally in very low doses. It cannot be ruled out that an increased growth of fungus, due to artificial fertilization, which then can be demonstrated to be found in food and consumed, can be a factor which increases the incidence of homosexual behavior in people.

One of the authors (Nilsson) has observed as a farmer that a change occurs in the crops with increased artificial fertilization of fields and forests, so that hay, grain and forest berries, for example, become mouldy more easily and more rapidly than when they are cultivated and grown without artificial fertilizers. And animals which are raised on crops which are cultivated this way become sicker and show both decreased capacity for reproduction and altered sexual behaviour (Roine et al. 1971).

Since fungi are well-known as producers of mycotoxins, it has been reasonable to attribute these changes to. the increased growth of fungi. In an earlier study the authors were able to show that blueberries from artificially fertilized forest land make hens infertile in that after eating these berries they laid eggs without shells or with defective shells. In large doses the blueberries were so toxic that all the hens died. There is reason to suspect that the toxic effects were caused both by mycotoxins and the absorption of very soluble aluminium compounds into the crops after artificial fertilization with ammonium nitrate or calcium nitrate (Nilsson & Lindahl, 1985).

The following study with rabbits has been carried out to test the effects of certain fungal toxins on sexual behavior.