Vegetarian diet benefits ‘slight’ in preventing type 2 diabetes

Recent reports that a meat-free diet could play a significant role in reducing the risk of type 2 diabetes have been downplayed by the NHS.

It follows reports by several national newspapers on research by teams at Keio University in Japan and The George Washington University School of Medicine in the US, published in Cardiovascular Diagnosis & Therapy.

The researchers concluded that, "Consumption of vegetarian diets is associated with improved [blood glucose] control in type 2 diabetes."

However, an NHS Behind the Headlines analysis of the research toned down the “misleading” report in The Daily Express and said “researchers actually found a vegetarian diet led to a quite modest fall in only one measure of blood glucose called HbA1C, a measure of blood glucose control.”

The study paper reported on a systematic review which combined the results of six trials that involved 255 people with type 2 diabetes. They examined whether vegetarian or vegan diets improved blood glucose control compared with a control diet.

Overall, the results of five of these trials found a vegetarian or vegan diet reduced HbA1c by 0.39%. There was no significant effect on fasting glucose levels, an assessment of how efficiently the body can process glucose in the short term.

Therefore, this slight reduction in HbA1c should not be regarded as a “cure” for the condition. As the researchers themselves pointed out, the reduction is less than you would expect if a patient was being treated with metformin.

The NHS report also suggested that the review had various important limitations, including the variable design and quality of the six trials included. So, it does not prove that a vegetarian or vegan diet is better for a person with type 2 diabetes, and any media claims of a "cure" for the condition are entirely baseless.

The NHS review added: “The current thinking is that there is no such thing as a cure for type 2 diabetes. The condition can be successfully managed, but not cured.

“The study is also only applicable to type 2 diabetes, so the headlines do not apply to type 1 diabetes.”

In conclusion the NHS site added: “Despite this being a systematic review of trials, the total number of participants was still quite small, at only 255. This is a very small number of patients, and it might be unwise to base any firm or generalisable conclusions on such small numbers.

“A vegetarian or vegan diet can be a healthy lifestyle choice for a person with type 2 diabetes if it provides balanced nutrition. But such diets can still be high in fat, salt and sugar if this is not controlled carefully.

“A healthy diet needs to be combined with regular exercise for people to be able to reap further health benefits, as well as avoiding smoking and only consuming alcohol at or below nationally recommended levels.

“Overall, this review does not appear to conclusively prove that a vegetarian or vegan diet is better for a person with type 2 diabetes. It certainly provides no evidence that this diet cures diabetes, as one of the news headlines suggests.

“Provided you do your homework, it is possible to eat healthily on a vegetarian or vegan diet. But if you do have type 2 diabetes, we recommend that you talk to the doctor in charge of your care before making any radical changes to your diet.”

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