Dairy foods, including cow’s milk, make up a substantial part of the typical western diet. Many contemporary humans consume milk for breakfast every morning, as well as regularly eat other dairy products such as yogurt and cheese. This is particularly true in the U.S. and in Northern European countries such as Finland and Sweden.
It’s not surprising that dairy consumption is so widespread in those parts of the world, seeing as most people who live there are able to consume lactose-containing foods without experiencing acute gastrointestinal distress and hold the belief that it’s healthy to consume milk and other dairy foods. This widely held belief has gradually been incorporated into the public’s mind over generations, helped by the dairy industry and public health authorities who both highlight the fact that dairy foods such as milk and yogurt are rich in calcium, protein, and vitamins.
What’s often forgotten is that dairy products are a very recent addition to the human diet. Throughout more than 99.6% of the evolutionary history of our genus, Homo, no humans on this planet regularly consumed the milk of another animal. Moreover, milk is a very special type of food, in the sense that its purpose is to induce mammalian, postnatal growth, development, and immune maturation. In other words, from a Darwinian point of view, it seems highly plausible that cow’s milk (or milk from another animal for that matter), as well as other dairy foods, don’t agree with the human biology.
Does milk really do the body good?
I’ve talked a lot about the health effects of dairy food consumption here on Darwinian-Medicine.com in the past. I’ve highlighted the fact that dairy products such as milk, cheese, and yogurt contain many troublesome compounds and have a less than ideal fatty acid profile, among other things. Moreover, I’ve argued that whey protein supplementation brings with it many negative health effects, some of which are related to gut health. What I haven’t done, is to delve into the research pertaining to how milk consumption affects mTORC1 signaling and growth.
Instead of reading up on that issue by myself and proceed to write about it here on the site, I decided to talk to an expert on the topic that I’ve seen mentioned many times throughout the years I’ve frequented the evolutionary health-oriented parts of the health & medical community. The person I’m talking about is Bodo Melnik.
I’ve never come across a researcher who appears to know as much about the epigenetic effects of milk consumption as Dr. Melnik. This guy is very high on the list of people on this planet who know the most about milk as it relates to human health and nutrition. In other words, when he speaks, you’d be wise to listen.
With that said, let’s get onto the interview…
1. Please tell us a little about yourself. Where did you get your MD and in what subject, and what have you been doing throughout your professional career?
Here’s a summary of my CV:
- Medical School University of Münster, promotion 1982.
- Visiting scientist 1982-1984 at the Cardiovascular Research Institute, School of Medicine, University of California San Francisco.
- Dermatology training as resident with Professor Dr. Gerd Plewig at the Department of Dermatology, Heinrich-Heine-University, Düsseldorf 1984-1990.
- Venia legendi in dermatology and Felix Hoppe Seyler Price awardee of the German Society for Laboratory Medicine 1989.
- Since 1991 senior lecturer at the Department of Dermatology, Environmental Medicine and Health Theory, University of Osnabrück;
- Since 1994 Associate Professor at the University of Osnabrück.
- Member of the European Society for Dermatological Research.
- Major research interests: acne, sebaceous and epidermal lipid metabolism, milk signaling, milk microRNA-mediated signal transduction.
2. How did you get interested in health, medicine, and nutrition, and in particular milk and the health effects of dairy food consumption, which have been the focus of much of your scientific work?
I have been trained on lipid and lipoprotein metabolism during my MD thesis in Germany and postdoctoral fellowship at the Cardiovascular Research Institute, UCSF, San Francisco. Here, I met Professor Peter Elias and got interested in epidermal lipid research and dermatology. During my habilitation at the Department of Dermatology, University of Düsseldorf, I was stimulated by Professor Albert Kligman and Professor Gerd Plewig and focused my research on sebaceous and epidermal lipid metabolism in acne and disorders of keratinization.
Stimulated by the epidemiological research of Harvard University (Prof. Walter Willett), it was my intention to clarify milk´s molecular mechanism aggravating or inducing acne vulgaris. I started out with the idea that milk provides a signaling system that modifies sebaceous gland function and lipogenesis. Primarily by translational research and without any industrial support, I unraveled milk´s signal transduction pathways with special attention to milk´s role in activating the central nutrient-sensitive kinase mTORC1, which promotes lipogenesis, growth and anabolism.
3. A lot of people grow up learning that cow’s milk is packed with high-quality protein, calcium, and vitamins and is an essential part of a healthy diet. Part of the reason for this is undoubtedly that the dairy industry has managed to imprint these ideas into the public’s mind via clever marketing campaigns. The fact that mammalian milk is a very powerful, complex substance that was designed, via natural selection, to promote the growth and development of suckling infants is given much less attention. What don’t people know about milk? How does the consumption of milk derived from another animal (e.g., a cow) affect the human body? What makes milk different from other foods that are a part of the human diet? I’m particularly interested in hearing about how milk consumption affects mTORC1 signaling and growth, which has been the focus of much of your research.
I came to the conclusion that milk is not a simple food but a most sophisticated endocrine signaling system of mammals to promote postnatal growth, let´s compare it to a specialized form of postnatal doping. I realized that milk provides two key signals fulfilling its task: essential branched-chain amino acids (BCAAs=milk´s hardware) and milk´s gene regulatory software (milk-derived miroRNAs transported in nanovesicles called exosomes). These two pathways enhance the activity of the kinase mTORC1. Over-activation of mTORC1 drives all diseases of civilization such as obesity, type 2 diabetes, cancer, and neurodegenerative diseases.
4. Dairy foods such as cow’s milk contain many different substances that don’t do an adult body good. Could you talk a little about one or more of these substances, for example miRNAs and/or nutrients such as casein or galactose?
Persistent activation of mTORC1 promotes age-dependent diseases. mTORC1 is activated by BCAAs such as leucine which are abundant in whey (14%) and casein (10%) proteins. Milk-derived microRNAs such as microRNA-148a not only promote lactation performance but also adipogenesis in humans. The microRNAs of milk are an arachaic signaling system, which explains their sequence homology between human and bovine species. They survive pasteurization and with the invention of the refrigerator were spread into civilized societies. Notably, microRNA-148a, the most abundant microRNA of milk, promotes lactation performance and milk yield and is overexpressed in high performance dairy cows.
With the selection of high performance dairy cows, pasteurization and refrigeration, civilized societies are persistently exposed to milk´s microRNA signaling. MicroRNAs control about 60% of human genes. With the introduction of bovine microRNAs into the human food chain, which are able to regulate human gene expression, humans got under gene control by another species, the dairy cow. The microRNA system of cow´s milk has the natural purpose to promote anabolism and growth of the calf, but not of human beings for life time. In contrast, fermentation, boiling and ultraheat treatment destroys milk´s micro RNA system, which explains why fermented milk products have a reduced risk profile.
5. In your scientific papers, you present evidence indicating that milk consumption is a risk factor for a variety of western illnesses. What types of diseases are particularly relevant in this respect?
Diseases promoted by milk consumption are acne, obesity, type 2 diabetes, prostate cancer, and Parkinson´s disease.
6. You are probably the world’s foremost experts on the role nutrition, and in particular milk consumption, plays in the pathogenesis of acne vulgaris. Could you please talk a little about your research in this area and the link between diet and acne?
There is accumulating evidence from epidemiological and placebo-controlled clinical studies that milk consumption promotes or aggravates acne vulgaris. During the last three years, dermatological societies changed their mind and accepted the link between nutrition and acne. There are two major drivers of acne: milk and hyperglycemic carbohydrates. Both activate mTORC1. Milk consumption increases the levels of BCAAs, insulin and insulin-like growth factor 1 (IGF1), which all activate mTORC1. High glycemic food as well enhances insulin levels and provides abundant energy (ATP), which activate mTORC1. Thus, milk and sugar (regular components of Western diet) synergize in the activation of mTORC1.
7. The dermatological community, as a whole, has not yet embraced the idea that diet plays a critical role in the pathogenesis of acne vulgaris, despite the fact that this idea is very much scientifically sound. Do you think dermatologists will soon incorporate dietary interventions/strategies into their treatment repertoire?
Academic dermatology was misled by a paper of Fulton et al in 1969, which compared the effect of chocolate bars with vegetable oil bars on acne. Unfortunately, the glycemic index of verum (chocolate) and control (vegetable bars) were identical, and thus showed no significant differences in acne outcome leading to the conclusion that diet has no effect on acne.
8. Milk is just one of the many dairy products that the modern, westernized man consumes on a regular basis. How do other dairy products, such as whey protein supplements and yogurt, compare to milk with respects to their impact on MTORC1 signaling, IGF-1 levels, growth, and the development of western diseases like acne vulgaris?
There are several reports including own clinical experience that show an aggravation of acne by whey protein abuse. This is not uncommon in the body building and fitness environment. Total dairy protein consumption is related to IGF1 serum levels, which promote sebaceous lipogenesis and acne. Cheese consumption increased in Germany from 1950 to today by the factor of 5, which demonstrates excessive dairy consumption in developed countries. Notably, fresh pasteurized milk is special, because it simultaneously transmits milk´s amino acid hardware and gene regulatory microRNA software, which are closest to milk´s natural program.
9. It’s generally believed that dairy food consumption is beneficial with respects to bone strength and osteoporosis risk. However, much research, including some large epidemiological studies showing that bone fracture risk correlates positively with dairy intake, questions the validity of this idea. What’s your take on the link between bone density/osteoporosis risk and dairy food consumption? What does the evidence show?
Recent epidemiological research, especially of the Harvard group around Walter Willett (see Homepage) provided strong evidence that dairy food and milk consumption increase the risk of bone (hip) fractures in people of higher age. Furthermore, Prof. Michaelsson of the Karolinska Institute (Sweden) showed a significant correlation between the dose of milk consumption and mortality risk.
10. What types of foods would you recommend that we should eat to optimize our calcium intake? Do you think people will put themselves at risk of calcium deficiency if they cut dairy foods from their diet?
There is abundant calcium in vegetables like broccoli and mineral water (see recommendations of the Harvard Homepage of the Willett group). Important for bone health is sufficient exercise and sufficient vitamin D supply (sun light). The amount of calcium in cow´s milk is intended to promote skeletal growth of the calf, which doubles birthweight after 40 days compared to human infants with 180 days. Furthermore, skelet weights of adult cows and humans differ significantly.
Thank you so much for your time.