Is a high-carb diet ‘poison’ to diabetics?

From The Times
London, UK
17 July, 2012

Is a high-carb diet ‘poison’ to diabetics?

John Naish

The NHS teaches that carbs are a key part of a balanced diet. But shunning them might help patients reduce insulin injections

When Martin Milton, 46, moved from London to New York last year, he saw an American doctor to get a fresh supply of insulin for his diabetes. “The doctor asked about my diet. When I told him, his initial reaction was that I was joking,” says the father of two. “He was astonished. He said that, to diabetics, my diet was poison.”

The surprising fact is that Milton’s food regime had been taught to him on an NHS course. The incident is emblematic of a growing controversy over the health service’s diet advice for diabetics. At the heart of this dispute lies widely differing beliefs about carbohydrates. The NHS course commends them — but the American approach says that diabetics should shun carbs whenever possible.

For healthy people with everyday food habits, the difference might sound like diet-faddism. But for people with type 1 or type 2 diabetes, it may make the difference between health and disability, even premature death. Indeed, Milton says that his new American-style diet has granted him a new lease of life.

Finding the right diet may help to contain Britain’s fast-growing diabetes epidemic. In the UK, 3.8 million people have diabetes and 7 million are at risk of developing it. Milton, a civil servant, was diagnosed almost 20 years ago with type 1 diabetes. He was given insulin pens with which to inject himself after every meal and once at night.

However, he never managed to control his blood-sugar levels consistently. “I have suffered a couple of big hypoglycemic attacks — seizures and fits — at night when I was asleep. It was very unpleasant for my wife,” he says. “At the time I was not trying any special diets, only avoiding sweet foods. I was given very little guidance. I felt pretty much at sea.”

Then, five years ago, specialists at St Thomas’ Hospital, London, invited him to a week-long NHS-funded diet course conducted by the diabetes patient education programme Dafne (Dose Adjustment for Normal Eating). It was here that he was taught the diet regime that shocked his US doctor.

“I was told that I could eat what I wanted, so long as I counted the carbs on my plate. This would enable me to work out my requirement for injected insulin,” Milton said. Injected insulin must be used by diabetics to keep blood-sugar levels within healthy limits. Blood-sugar levels are particularly raised by carbohydrates, which the body turns into glucose. Insulin works by stimulating the cells within the body to take up the glucose in the blood.

Dafne is offered at more than 140 diabetes clinics in the UK and Ireland, and is considered part of routine care for type 1 diabetes. The philosophy of its teaching is that, rather than taking a fixed daily dose of insulin and having to stick to a diet that matches it, patients can rate their own meals for carbohydrate content and then adjust their insulin doses to match.

“I was told that 60 per cent of my diet should be comprised of carbs. I was encouraged to eat pasta and white rice. These were the things to measure,” Milton says. “My blood levels improved generally during the course. But later I still had big hypos and my overall control did not get better.” In fact, Milton’s condition was worsening. His blood-sugar levels were generally too high and his eyesight was starting to show signs of deterioration. Then, last year, he moved to New York and met the doctor who placed him on a different regime. “He told me to cut down as many carbs as possible and fill up with salads and greens.”

Milton was sceptical, but decided to try. He began a low-carb regime with no rice or pasta. Instead, he has salad for lunch, with other meals comprising vegetables, nuts and cheese. Since then, he says, his health has been transformed. “The doctor must be right. If you reduce your carbs, you can reduce the amount of insulin you take to balance it. I noticed that very quickly I was using a fraction of the insulin I had needed.”

Still, Milton worried if there was anything wrong with the regime.

The most publicised concern is that it may dangerously raise cholesterol levels, as it relies on fat such as cheese for energy to compensate for the lack of carbohydrates. He e-mailed his NHS consultant, who insisted on seeing him when he visited Britain in February. Tests showed an unprecedented improvement in Milton’s blood-glucose levels. His weight was far healthier too — down more than 33lb, to 14st. What’s more, his blood cholesterol levels had not risen.

Medical research increasingly supports low-carb diets fordiabetes sufferers. A four-year study of 48 people with type 1 diabetes who followed a low-carb diet found a lasting improvement in the 24 who managed to stick to the regime.

The Swedish research was published in the respected journal Diabetology & Metabolic Syndrome.

The effects of low-carb diets have been studied more extensively in type 2 diabetes. In May, a two-year study at Sweden’s Linköping University showed that low-carb, high-fat diets may have a better effect on blood-sugar levels than high-carb diets. It compared 61 patients on either a low-carb, high-fat diet, or a high-carb, low-fat diet. It found a “clear improvement” in the blood-sugar levels of the low-carb patients within six months of starting the diet. Patients were able, on average, to drop their insulin doses by a third, the study in the journal Diabetologia said. The cholesterol levels of the patients improved, with an increase in their average level of “good” HDL cholesterol. No such improvements were seen in the high-carb, low-fat group.

Fredrik Nystrom, a professor of medicine, who co-authored the study, said: “You could ask yourself if it really is good to recommend a low-fat diet to patients with diabetes.”

In America, opinions have already swayed towards low carbs. The American Diabetes Association changed its advice on low-carb diets in 2008. It now considers them to be an effective treatment for short-term weight loss among obese people suffering from type 2 diabetes.

So why does the NHS persist with recommending high-carb, low-fat diets? The concern is that people with diabetes are known to have an increased risk of heart disease — and the high fats in low-carb diets are feared to worsen this. Instead, the Department of Health recommends that diabetics try to eat low-GI (glycaemic index) carbs such as brown rice and wholemeal grains, which are turned more slowly into sugars by the body, and thus cause fewer “spikes” in blood-glucose.

But “diabetic activists” such as the online community, via diabetes.co.uk, are critical of this approach. “Even low-GI carbohydrates are absorbed too quickly for many people with type 2 diabetes to prevent high post-meal blood sugar levels,” it says. “Department of Health guidelines are yet to take this into consideration, as they recommend 225g to 300g of carbohydrate a day. Why are the guidelines set as they are?”

But there may indeed be some cause for caution. In March, researchers from Warwick Medical School warned that high fat intake may provoke inflammation in diabetics’ arteries that can cause heart disease.

Dr Alison Harte, a University of Warwick research fellow, told a Society for Endocrinology conference that her studies showed how high-fat meals led to a large amount of gut-derived bacteria in the blood — and this was higher in diabetics, due to a “leaky gut”.“This creates conditions within the body that trigger inflammatory reactions which ultimately can cause a number of conditions such as heart disease,” she explained.

As a result of such conflicting evidence, British experts are giving low-carb regimes only a cautious welcome. Last year, Diabetes UK changed its advice for people with type 2 diabetes to say that a low-carb diet where less than 45 per cent of calories come from carbohydrates “may be suitable for a year”. Other expert organisations are following suit.

Why only a year? Chris Cheyette, a dietitian at King’s College Hospital and a spokesman for the British Dietetic Association, says: “We only have good enough research evidence to say that it is safe to spend a year on low carbs.”

Mr Cheyette adds that the best option for diabetics considering low-carb diets is to consult a dietitian. The only problem is that NHS dietetic services are struggling to keep up with demand from Britain’s ever-growing diabetic population. The waiting lists for advice are, as a result, constantly growing. “There simply are not enough of us dietitians out there,” he says.

Given the huge cost of caring for people with diabetic complications — one in five NHS hospital inpatients has diabetes — that seems like a false economy.

http://www.thetimes.co.uk/tto/health/article3477195.ece