Diet & Nutrition: 5 Ways to Prevent Type-2 Diabetes

EatingWellLivingWell.jpgBy Richard Béliveau, Ph.D.,
and Denis Gingras, Ph.D.

Given the serious consequences emanating from insulin resistance and Type-2 diabetes, preventing this disease is certainly our best weapon in reducing the damage caused by a surplus of blood sugar. Luckily for us, the preventive potential is extraordinary: Adopting a healthy lifestyle can prevent up to 90% of Type-2 diabetes cases! To see how we can reduce the risk of diabetes, let us review some lifestyle factors.

Controlling body weight – Given that excess weight and obesity are instrumental in the development of Type-2 diabetes, maintaining a normal body weight is an essential aspect of any preventive approach. The most spectacular illustration of how weight loss can influence the risk of diabetes is undoubtedly the effect of bariatric surgery (reducing stomach size) on morbidly obese people. Radically reducing the size of the stomach rapidly decreases obesity and almost completely eliminates Type-2 diabetes!

However, it is neither necessary nor desirable to undergo this type of surgery to reap the benefits of weight loss: Losing just 5 kg, even over several years, can reduce the risk of diabetes by 50%! At a time when overweight has become the norm rather than the exception, Type-2 diabetes undoubtedly illustrates the dangers of excess weight and the need to be as slim as possible in order to prevent this disease.

Controlling glycemia – You can also significantly reduce the risk of diabetes by paying particular attention to the amount and especially the type of carbohydrates: that is, the sugar in your diet. There are three main types of carbohydrates.

The first is simple sugars – like those in fruits, dairy products, maple syrup, or honey – and sugars added to various products sold in grocery stores. Added sugar is quite significant: In 2001, it represented more than 10% of the calories consumed by Canadians, or the equivalent of 60 g (12 teaspoons) of sugar a day! This sugar surplus is sometimes difficult to identify as the industry uses many sources of sugar in its preparation of food products. But make no mistake. When a product label uses terms like sucrose, dextrose, fructose-enriched corn syrup, glucose-fructose, malt syrup, etc., it can mean only one thing: sugar has been added! The closer these items are to the top of the ingredient list, the more of them the product contains.

The second main form of sugar is starches. These are created by combining a number of sugar molecules. Starch is found in cereals, potatoes, and certain vegetables and legumes. Generally, the sugar present in foods in starch form is digested more slowly than simple sugars. Conversely, all starches are not digested at the same rate: For example, potato starch has a structure that breaks down into sugar very quickly while legume starches are much more resistant.

The third main form is dietary plant fibres, found only in plant products such as vegetables, fruits, and whole grains. These fibres are so complex that our stomach cannot digest them and only the bacteria present in our intestines can extract a small amount of their sugar content.

The main difference between the various types of carbohydrates is how fast they are absorbed by the intestine and transported into the bloodstream. In the case of simple sugars, their rapid assimilation forces the pancreas to react by secreting a large amount of insulin. Conversely, in the case of dietary plant fibres or complex starches, the intestine breaks down these sugars much more slowly, causing sugar to appear gradually in the blood and produce less insulin. To distinguish the effects of carbohydrates on blood glucose, we use the concepts of glycemic index and glycemic load.

Ingesting a food with a high glycemic load, such as corn flakes, rapidly increases the blood glucose level, which is accompanied by a massive secretion of insulin striving to absorb all the sugar. However, it may happen that the amount of insulin produced by the pancreas in response to this sugar level is too great, which can result in excessive glucose absorption, and paradoxically, a hypoglycemic state a few hours after eating a meal. This is not a desirable outcome as the lack of glucose in the blood greatly stimulates the centres involved in appetite control, causing a craving for more food to raise the glucose level. If repeated excessively, these fluctuations will not only wear out the pancreas but also promote obesity. Actually, insulin helps convert sugars into fats, as well as store them in the adipose tissues.

Conversely, consuming foods containing complex carbohydrates (with a low glycemic load, such as whole grain products and legumes) produces a much smaller amount of glucose and insulin in the blood. Under these conditions, the glycemia is stabilized over a longer period, without hypoglycemic episodes. By avoiding blood glucose fluctuations, this type of carbohydrate reduces insulin production and prevents overloading of the pancreas. In addition to being important for diabetics or pre-diabetics, who must maintain a stable glycemic level, consuming complex carbohydrates with a low glycemic load is a dietary change that can have a big impact on diabetes prevention in general.

Choosing dietary fats.
The type of dietary fat can also exert a huge influence on the development of Type-2 diabetes. Certain saturated fats, for example, promote inflammation, indirectly causing insulin resistance. Conversely, oleic acid, the main fat in olive oil, has an anti-inflammatory action, thereby reducing the risk of insulin resistance. It is noteworthy that omega-3 fats can improve the insulin response of our organs. As for heart disease prevention, using olive oil as the main fat combined with sustained omega-3 intake is a key element in diabetes prevention.

Physical exercise. Besides its central role in preventing cardiovascular diseases, regular physical exercise is essential for Type-2 diabetes prevention. Muscles are the main organs involved in the absorption of glucose in response to insulin. Therefore regular physical exercise, by maintaining optimal muscular function, improves our sensitivity to insulin, thus ensuring stable blood glucose levels. A study of pre-diabetics who presented with, among other things, hyperglycemia upon fasting (over 1.1 g of glucose per litre) and high blood pressure, showed that regular exercise (150 minutes a week) over three years reduced glycemia considerably more than if they had taken a frequently used molecule (metformin) to reduce blood glucose levels. Regular exercise not only reduces glycemia but notably improves blood pressure, an extremely positive effect for heart disease prevention and one not seen in treatment with hypoglycemic drugs. In other words, while molecules like metformin are vital allies in fighting disorders responsible for diseases like Type-2 diabetes, we must never underestimate the remarkable effect of lifestyle changes such as physical exercise on a number of processes induced by these diseases.

Adding a little spice to food! As incredible as it may seem, certain spices can be instrumental in diabetes Type-2 prevention. The most obvious one is undoubtedly cinnamon, an aromatic substance that improves glucose tolerance and has the ability to interfere with the creation of glycation products that damage blood vessel linings. This property appears to be widespread in the plant kingdom as spices and seasonings such as Jamaican allspice, black pepper, thyme, and many other herbs can also block glycation reactions. Turmeric also seems to reduce blood glucose levels, which is why it is used in traditional Indian medicine (Ayurveda). In addition, turmeric’s powerful anti-inflammatory activity is a very good preventive weapon for reducing the damage caused by a sugar surplus in the cardiovascular system. Spices continue to surprise us!

Excerpted from Eating Well, Living Well Copyright © 2009 by Richard Béliveau, Ph.D., and Denis Gingras, Ph.D. Translated by Valentina Baslyk. Excerpted by permission of McClelland & Stewart. All rights reserved.