Are whole grains better for your health than refined ones?

Official nutritional recommendations and the Nutri-Score encourage the consumption of whole grains over refined grains. But are these “whole grains” always better than refined grains? There is a trap.

Our expert on this subject: Professor Jennie Brand-Miller, professor of human nutrition at the University of Sydney.

Doctors, dietitians, nutritionists… all urge us to choose our carbohydrates better, and turn to “whole” foods. These messages are transformed into a sales argument by the agri-food industry which does not hesitate to point out to us on each product which contains the slightest grain of whole wheat: “Guaranteed with whole grains“…Yes, but what are these “whole grains”? Should we strive to meet this nutritional recommendation? Explanations.

The impact of ultra-processed foods

When a food or meal high in carbohydrates is consumed, blood sugar levels rise shortly after. However, whole grain products generally have a more favorable glycemic response than refined grain products. Does this mean that a processed food, “whole” breakfast cereals for example, are good for your health, particularly when they have a Nutri-Score A or B? In reality, the effects of the transformation must be taken into account.

An analysis was published that looked at randomized controlled trials comparing postprandial blood glucose and insulin responses to various forms of oats: intact or as thick “flakes” or made thin to give instant flakes. Results: compared Unlike oats consumed as intact grains, those in flaked form led to an increase in blood sugar and insulin response. The response was all the stronger as the flakes were fine.

To be manufactured, the oat flakes are subjected to hot steam and then crushed. “This means that when the structural integrity of the oat grains is disrupted, their matrixindicates Dr Anthony Fardet, author of Stop Ultra-Processed Foods, we lose the benefits of oats on blood sugar.” This study shows that it is necessary to take into account the impact of processing on the nutritional qualities of a food.

Real and fake whole grains

A 2012 study reviewed the impact of choosing the type of carbohydrate (refined/white or whole) on health. To do this, the researchers examined all publications between 2000 and 2010, 135 in total, and found that the majority of them show no link between the consumption of refined grains and the risk of diseases such as diabetes, cardiovascular disease or being overweight. Several meta-analyses have since reported the same results.

“This publication, says Professor Jennie Brand-Millerraises questions about nutritional recommendations. When health authorities recommend eating more whole grains, they say that we should therefore eat more fiber, which will probably be the case, more vitamins and minerals, which is unlikely to be the case, and lower glycemic indexes, which will not be the case at all. The truth is that for most grain products today, the “whole” version and the “refined/white” version both have high glycemic indexes.. This is due to the degree of processing of certain whole foods.”

The glycemic index measures the ability of carbohydrate foods, such as grains, to raise blood sugar. The idea conveyed by some nutritionists that cereal foods are “slow sugars” is clearly inaccurate most of the time, even when these cereals are “whole”.

“I suggest, says Professor Brand Millerthat the term “complete cereals” be redefined as “ingredients which contain the germ, the endosperm, the bran but also the glycemic characteristics of the original cereal.” It is only from this moment that it becomes possible to observe the health benefits of these foods. “Complete” products sold commercially have generally been cooked, crumbled, pulverized, grilled, blown beyond what one can imagine. We are very, very far from the original cereal grain.”

There is also a very simple example to illustrate what Jennie Brand-Miller describes: when you buy puffed rice cakes, the ingredients are represented by more than 90% whole grain rice. And yet the glycemic index of these products is catastrophic: close to 100, a real bomb for your pancreas and your blood sugar.

There are very few clinical studies that have compared diets that differ only in the type of cereal consumed (refined or whole grain). The largest was carried out in the United Kingdom. The researchers asked 316 overweight people (men and women) to replace refined foods in their diet with their whole-grain equivalent. After 16 weeks, no difference was observed in terms of cardiovascular risk (cholesterol, triglycerides, insulin sensitivity, markers of inflammation) between the experimental group and the control group.

The bottom line is that whole grain products are generally preferable to refined versions, unless they are ultra-processed. We must therefore eat real food, that is to say real food; if they are cereal products, complete but little processed. And to help you choose your foods better, the LaNutrition.fr team has published two short guides: one which contains the glycemic index of more than 700 foods: to discover here, and the other which lists the good, minimally processed products in the supermarket, aisle by aisle (they are not identified by the Nutri-Score).