The latest theories about the dietary and environmental causes of diabetes and how to minimize its effects.
Diabetes mellitus affects around 2 per cent of the population and its incidence is becoming more common with 60,000 cases currently diagnosed each year.
What triggers the condition is not fully understood. It does seem clear, however, that like many ailments, its increased prevalence is linked to the Western lifestyle.
A 12 year study published in the British Medical Journal (H. Bodansky et al, 18 April 1992) shows that environment is a major factor. The researchers found that when children of families from an area where diabetes is rare move to an area where it is more common, they show a corresponding rise in the disease. The incidence of diabetes in Asian children in Bradford went from 3.1/100,000 per year in 1978-1981 to 11.7/100,000 per year in 1988-1990. The level for indigenous children remained constant at 10.5/100,000 per year.
Prescribed drugs and diet are thought to have a role as a trigger. A study looking at nutrients and food additives suggests a diet with large amounts of foods rich in protein and carbohydrate, along with food additives such as nitrosamines, may increase the likelihood of developing diabetes (Dr Gisela Dahlquist et al, BMJ, 19 May 1990). Other research suggests long term use of antihypertensive drugs thiazides, betablockers, hydralazine increases the odds of diabetes by a factor of around 1.7, independent of any other risk factors (Dr Elinar Skarfors et al, BMJ, 28 September 1991). Stress is also thought to play a part.
Diabetes is divided into two types: insulin dependent and non insulin dependent. With the first, which strikes younger people, the pancreas stops producing any insulin. (Insulin enables the body to convert sugar into energy; without it, sugar remains in the blood.) Treatment is by daily injections of insulin and by following a careful diet to match the amount of energy taken in with the amount of insulin injected so that blood sugar levels stay as near normal as possible.
The second type is also known as middle age onset diabetes. With this type, the pancreas stops producing sufficient insulin to counteract the amount of sugar in the blood. It is often treated by diet alone, or by diet and insulin stimulating drugs which have their own side effects (see below). Both types of diabetes can be associated with a range of side effects, commonly hypoglycaemia, where the blood sugar falls too low, causing the diabetic to pass out if not caught in time. In the longer term, raised blood sugar levels can lead to blindness, heart disease, kidney damage and gangrene.
Obesity is thought to be a major factor in triggering type two diabetes; however, a study published in The Lancet (28 September 1991) suggests regular exercise may help stave off diabetes, even in those who are overweight. The researchers tracked 87,253 American women between the ages of 34 and 59 for an eight year period. "Physical activity was associated with a greater reduction in risk of NIDDM (non insulin dependent diabetes mellitus) during this period for women exercising at least once a week compared with sedentary women," they said.
Leading nutritional doctor Stephen Davies believes low levels of chromium which tends to decrease with age may be a trigger of type two diabetes. "We have many examples of patients whose glycosolated haemoglobin [the part of the blood tested to measure blood sugar levels] has come down into the normal range once their chromium levels are raised," he says. Supplements of chromium and "judicious dietary intervention" may enable many more diabetics to control their condition without resorting to drugs. Recognized side effects of insulin stimulating drugs are nausea, anorexia, diarrhoea, skin allergies, reversible leucopaenia (reduction in the number of white corpuscles in the blood), thrombocytopenia (blood platelets reduction) and transient changes in liver enzymes. Davies recommends that elderly diabetics boost their chromium intake with 20-30 brewer's yeast tablets a day.
Chromium levels may also be depleted in insulin dependent diabetics. Supplementation can improve control and because chromium allows insulin to work properly may allow some diabetics to reduce their insulin doses, says Davies. (He warns, however, to be aware that greater insulin efficiency may increase the number of hypoglycaemic episodes hypos until the insulin dose is correspondingly reduced.)
Dr Davies says dietary supplements may also be helpful in staving off other side effects. Diabetics with symptoms of eczema or thrush should be tested for zinc deficiency. Zinc supplements may also help the healing of resistant leg ulcers, along with doses of vitamin C. (Davies recommends 1-3 g of vitamin C and 20-80 mg zinc a day.) Vitamin C is also helpful with a host of other side effects; it strengthens weak blood vessels associated with eye disease and reduces cholesterol levels in blood. Diabetics who have suffered from ketoacidosis (where severe insulin deficiency has caused fat breakdown leading to acidification of the blood) are likely to be deficient in magnesium. Potassium levels may also be depleted.
Other recommended vitamin supplements are B6 and B12 to aid control and reduce the likelihood of nervous system disorders and vitamin E, which helps minimize damage to small blood vessels. Increased consumption of polyunsaturated fatty acids and their derivatives such as evening primrose oil and vitamin C will help reduce the levels of fats in the blood. Dr Davies also recommends eating plenty of salmon, mackerel, herring and linseed oil to reduce the risk of blood platelet clumping which can cause eye disorders.
An underexplored factor which may affect diabetic control is the impact of food allergies.Dr Davies says animal studies have shown that certain foods may have an impact on blood sugar levels, which have nothing to do with the amount of carbohydrate ingested. Such allergies may often be masked, so Dr Davies recommends using a process of self testing to isolate foods which may provoke an allergic reaction if sugar levels are fluctuating for no apparent reason. One such substance is bovine serum albumin, a protein in cow's milk, which may trigger an autoimmune response that destroys pancreatic cells in genetically susceptible individuals. A recent study (The New England Journal of Medicine, 30 July 1992) examined the blood of 142 children with IDDM and found that all had elevated anti-BSA antibodies, which the University of Toronto researchers concluded had precipitated pancreatic dysfunction.
Diabetic pregnancies - whatever the mother's state of health - are still deemed by standard medical thinking to be high risk. Dr Michel Odent a leading pioneer of natural childbirth rejects such a blanket approach. "Generally speaking, any label of high risk brings with it its own risk," he says, and should, therefore, be avoided. This high risk tag means that the whole paraphernalia of science's attempts to improve on nature will be wheeled out when a diabetic woman is to give birth.
Inductions and caesareans are still routinely inflicted on diabetic mothers in many hospitals. Such drastic intervention in the natural birth process might have been necessary in the past, when it was much harder for diabetics to keep their blood sugar levels well controlled; the excess insulin, which encourages growth, resulted in oversized babies. However, with the advent of more accurate blood sugar testing and improved dietary advice, routine inductions and caesareans are anachronistic.
Many hospitals still persist in inducing diabetic mothers at 38 weeks. Anna Knopfler, who set up the self help group Diabetic Pregnancy Network, suggests asking your doctor what percentage of diabetic births at your hospital are induced. If it is high, you should shop around for a hospital with a more enlightened attitude, and make sure your doctor knows that you want to go to term unless there are real rather than just feared complications.
Dr Odent says there is no reason why a healthy, well controlled diabetic shouldn't have a natural birth. By that, he means privacy, comfort, familiar surroundings and freedom to move around. Even if home birth isn't yet an option for many diabetics, you should try to mimic those ideal conditions as far as possible.
A speedy birth is particularly important for diabetics, yet medicine contrives to create conditions where that is unlikely to happen naturally. Dr Odent says all mammals instinctively seek privacy when giving birth for good reason. Undisturbed labour allows the "primitive structures" of the brain which should be active during birth to come to the fore. "When you take a woman and observe her and subject her to strong light, you make it impossible for her to make this change in her conscious level," he says.
The hospital setting itself, therefore, slows up the birth process and makes it more hazardous. To counter a problem of its own design, medicine has designed a daisychain of interventions.
In the British Diabetic Association's pregnancy pack,it describes a mother strapped up to four drips during labour; hormones to precipitate contractions; glucose; insulin; and a drip to raise her blood pressure which was expected to fall as a consequence of the epidural she had been given.
The process of intervention is self perpetuating. The pain and distress accompanying an induced birth will in themselves help make the diabetic's blood sugar levels unstable, which increases the likelihood of needing glucose and insulin drips.
Before selecting your hospital, check whether you can elect to manage your own insulin doses during labour.
According to research published in The Lancet (13 June 1992), birth without infused insulin and glucose remains rare. Some 87 per cent of respondents (representing 128 of the UK's 218 health districts) routinely use insulin and glucose drips, citing "standard practice" or supposed "difficulty in managing without a drip". The report's authors are in no doubt that drips are used simply for the convenience of hospital staff; drips make for "ease of administration and simplicity of approach, and can be used by staff who may not be experts in diabetes management." Just 2.3 per cent of respondents had ever elected to manage labour in eight insulin dependent women without drips. (Instead, they used a regime of 4-6 hourly insulin injections and sips of glucose taken as necessary which leaves the diabetic and her partner far more in control.) In all eight: "The outcome of the pregnancy was a live delivery without major neonatal problems."
In some hospitals it is still standard practice for the baby to be taken away for 24 hours after birth for observation and to be tested for hypoglycaemia. Dr Odent deplores this practice. "The best way for the baby to avoid hypoglycaemia is for it to get plenty of colostrum as soon as possible," he says. Again, you should check with your hospital whether you will be able to keep your baby with you after the birth.
Unsaturated fats aid the action of prostaglandins as important cell regulators during the birth process. They are essential in initiating the process and in maintaining strong contractions which will expedite the birth. Low insulin levels and saturated man made fats both have the effect of inhibiting the working of prostaglandins. Diabetic mothers should eat plenty of foods containing unsaturated fats corn oil, primrose oil, milk, liver and kidney and avoid those containing man made fats, including margarines. (Unsaturated fat also helps the baby's brain to grow.) Odent also advises supplementing the diet with zinc, vitamin C, vitamin B and magnesium.
Fiona Bawdon, formerly of Balance, the BDA's magazine, is a WDDTY contributing editor.