“Milk is not a bad food!”

Jean-Michel Lecerf, what are the proven nutritional benefits of milk?

The first benefit is the exceptional composition of the milk in terms of proteins. They are among the most complex and complete and include both fast and slow proteins. In particular, a study has shown that a protein isolated from milk makes it possible to considerably increase the plasma level of certain amino acids, in particular leucine in the blood, for the prevention of muscle aging.

Next, the fats in milk contain the most different types of fatty acids. This does not mean that all the fats in milk are interesting, but certain minor fatty acids have extraordinary effects on a lot of functions.

Finally, milk is the food that contains the greatest diversity of micronutrients in number and quantity, including calcium of course, but also iodine, phosphorus, selenium, magnesium … As regards vitamins, the contribution of milk is strong since it would provide between 10 and 20% of the recommended intakes.

Has research been able to prove that drinking milk is beneficial for health?

Indeed, nutrition is one thing, but health is another. Increasingly, research is describing exceptional health benefits in unexpected ways. First, there is a link between the consumption of milk and the prevention of metabolic syndrome and type 2 diabetes. Studies are very numerous and the cause and effect relationship is very probable. We know this thanks to certain very specific marker fatty acids that are only found in dairy fats. Then, research tends to benefit from milk on the cardiovascular risk and in particular on the first heart attack. It could be related to calcium but nothing that is not certain. There is also a favorable effect of milk on weight for reasons of satiety and satiety, a clear and confirmed decrease in colorectal cancer and a definite interest of milk in the prevention of age-related sarcopenia and undernutrition.

What about the supposed link to osteoporosis?

In terms of fractures, there is a lack of formal intervention studies. Observational studies, on the other hand, clearly show that those who consume milk are at lower risk than those who do not. As long as you do not consume too much, according to the latest BMJ study (the risk of early mortality is almost doubled in women who drink 3 glasses of milk a day or more according to this study, editor’s note). Intervention studies carried out on bone mineral density do show a favorable effect, but there are too few studies available on fracture and osteoporosis to establish a definite link.

Conversely, have you heard of studies that demonstrated the link between milk and certain conditions?

There are quite a few studies implicating milk in the occurrence of prostate cancer. The WCRF (World Cancer Research Fund International), however, has just issued a very interesting opinion where the responsibility for milk has been reclassified as “limited evidence”. This means that it is still under review. Observational studies show that if there is a link, it is for very high intakes, of the order of 1,5 to 2 liters of milk per day. Ongoing experimental studies in animals show that high-dose calcium is associated with an increased risk and, conversely, dairy products are associated with a decrease. Caution is therefore to advise not to consume very large quantities of dairy products, that is to say at least one liter or two liters, or the equivalent. It seems logical.

Milk is also often accused of containing growth factors that can cause cancer. What is it really?

There was indeed a whole controversy that was the subject of a referral to ANSES on these growth factors. As it stands, there is no established cause and effect relationship. However, it is obvious that one should not consume too much protein.

There are growth factors in the blood that are promoting factors like estrogen. And it’s also found in dairy products. These factors are very well absorbed in the toddler, and it works rather well because they are present in the milk of women and they are used to make the child grow. But, over time, there are enzymes that cause these growth factors to stop being absorbed. And anyway, UHT heating turns them off completely. In reality, therefore, it is not the growth hormones in milk that are responsible for the levels of growth hormones circulating in the blood, it is something else. It’s the proteins. Proteins cause the liver to make growth factors that are then found in the circulation. Too much protein and therefore too many growth factors are therefore not desirable: this contributes to the large size of children, but also to obesity and perhaps, in excess, to a tumor promoting effect. Children consume 4 times too much protein compared to their recommended intake!

But milk is not the only one responsible for this phenomenon: all proteins, including those obtained from plants have this effect.

Do you understand that we are turning away from milk in favor of certain alternative products such as vegetable drinks?

In nutrition, there are more and more people who go on a crusade against food, Ayatollahs. This can sometimes even concern certain health professionals who are not necessarily competent in nutrition and who lack scientific rigor. When you are a scientist, you are open to everything: you have a hypothesis and you try to find out if it is true. However, the detractors of milk do not go in this direction, they claim that milk is harmful and try everything to demonstrate it.

Several nutritionists report that some people feel much better after they stop consuming milk. How do you explain it?

I am familiar with this phenomenon since I am also a clinician and have probably seen 50 to 000 patients in my career. There are several scenarios. First, milk can be responsible for disorders like lactose intolerance. This causes troubles, not major but annoying, which are always linked to the quantity and quality of the dairy product consumed. Allergies to cow’s milk proteins are also possible. In these cases, stopping the milk will actually cause the disappearance of the disorders related to its consumption.

For other categories of people, the feeling of well-being after stopping milk may be linked to a change in eating habits. These effects are not necessarily linked to a particular food, but to a change. When you change your habits, for example if you are fasting, you will feel different things about your body. But will these effects be sustainable over time? Are they attributed to milk? The placebo effect should not be neglected either, which is a major effect of medicine. Studies of people who are lactose intolerant have shown that their symptoms improve when they are given lactose-free or lactose-free milk but without telling them which product they are drinking.

Critics of milk argue that the milk lobby would influence the PNNS (Program National Nutrition Santé). How do you explain that the authorities recommend 3 to 4 dairy products per day while the WHO recommends only 400 to 500 mg of calcium per day (a glass of milk provides about 300 mg)?

The milkmen do their job but they are not the ones who dictate the recommendations to the PNNS. It is no wonder that dairy lobbies are looking to sell their products. That they seek to influence, perhaps. But in the end, it’s the scientists who decide. It would shock me that the PNNS like the ANSES are in the pay of dairy products. For the WHO, on the other hand, you are right. The WHO recommendations do not have the same purpose at all as those of the health security agencies or the PNNS which provide recommended dietary intakes. In fact, there is a lot of discrepancy. The WHO assumes that they are aimed at the entire world population and that the goal is at least to reach a limit for people who are at very low levels. When you have populations that consume 300 or 400 mg of calcium per day, if you tell them that the goal is 500 mg, that’s a minimum. These are very basic safety recommendations, if you look at what the WHO recommends for calories, fat, it’s not the same either. Study the recommendations in terms of calcium from all the food safety agencies in many Asian or Western countries, we are almost always at the same level, i.e. around 800 and 900 mg of recommended calcium. Finally, there are few or no contradictions. The purpose of the WHO is to fight against malnutrition.

What do you think of this theory that milk increases the risk of chronic disease?

It is not excluded that milk increases the risk of intestinal, rheumatic, inflammatory diseases… It is a possible hypothesis, nothing should ever be ruled out. Some make this claim because of increased intestinal permeability. The problem is that there is no study that accredits it. It’s really annoying. If there are researchers who observe this phenomenon, why don’t they publish them? In addition, when we look at the studies that have already appeared, we do not see this at all since they show that milk would have an anti-inflammatory effect. So how do you explain that clinically milk becomes pro-inflammatory? It is difficult to understand… Some of my patients stopped the milk, they had some improvements, then after a while, everything came back.

I am not defending milk, but I do not agree with the idea that milk is passed off as a bad food and that we have to do without it. This is ridiculous and it can be dangerous especially in the coverage of recommended intakes. It always comes back to the same thing, eating too much of any food is not good.

Go back to the first page of the big milk survey

Its defenders

Jean-Michel Lecerf

Head of the Nutrition Department at the Institut Pasteur de Lille

“Milk is not a bad food!”

Reread the interview

Marie-Claude Bertiere

Director of the CNIEL department and nutritionist

“Going without dairy products leads to deficits beyond calcium”

Read the interview

His detractors

Marion Kaplan

Bio-nutritionist specialized in energy medicine

“No milk after 3 years”

Read the interview

Herve Berbille

Engineer in agrifood and graduate in ethno-pharmacology.

“Few benefits and a lot of risks!”

Read the interview