Myths about milk – Milk and cholesterol

Prof. RNDr. Aleš Macela, DrSc.

Prof. RNDr. Vanda Boštíková, Ph.D. 

(Part II.)

If we accept the fact that humans are mammals and that breast milk is their only source of nutrition for a certain period after birth, then we must also accept that milk has a certain significance for humans and their health. It is therefore surprising that there is so much doubt surrounding milk consumption and its effects on health.

Whichever website you visit on the subject of milk and health, you will learn that it is better to approach milk with a certain degree of caution. This mainly applies to whole milk (1, 2). The information provided includes statements such as: whole milk increases the risk of diabetes and heart disease and can lead to weight gain due to excess calories (3). The authors refer to the American Heart Association, which, however, discusses the issue of fats containing saturated fatty acids in general (4). There is a whole range of such false information (5).

Let’s stick to questions about cow’s milk and cholesterol. The total cholesterol content of cow’s milk is relatively low and varies according to its total fat content. Whole milk therefore has a higher cholesterol content (10 mg/100 ml) than semi-skimmed milk (8 mg/100 ml) or skimmed milk (2 mg/100 ml) (6). It is therefore more important to focus on fat content rather than cholesterol.

Freshly milked cow’s milk contains an average of 4% easily digestible milk fat. It contains saturated fatty acids, which account for approximately 70% of all fatty acids found in milk, of which there are more than 400 different types. The rest is made up of monounsaturated and polyunsaturated fatty acids (7-9). Among the various types of fatty acids, milk also contains short-chain fatty acids, which are very well absorbed and contribute to the formation of the internal environment of the digestive tract, including the physiology of the large intestine, and participate in various signaling mechanisms between the functional systems of the body.

The effect on the composition of the intestinal microbiota is significant, as it is another important source of these regulatory molecules (10-11). Polar lipids are also functionally important in milk. They are contained in the membrane of milk fat globules and are a source of sphingomyelin, phosphatidylcholine, and phosphatidylethanolamine, as well as certain amounts of phosphatidylserine, phosphatidylinositol, and glycosphingolipid, i.e., lipids necessary for the construction of biological cell membranes (12).

Recent basic and clinical research on the health effects of milk polar lipids suggests that they may have a beneficial effect on dysfunctional lipid metabolism, intestinal dysbiosis, inflammation, cardiovascular disease, intestinal health, and neurological development. In addition, they may also lower blood cholesterol (13-14).

Like everything else, milk consumption has its pros and cons. People who do not have or have lost the lactase enzyme (lactose intolerance) or are allergic to cow’s milk proteins will have problems consuming milk. For others, milk can be a suitable component of the diet due to its content of calcium, phosphorus, potassium, magnesium, sodium, and other elements, including trace elements and a range of vitamins (A, B1, B2, B6, and B12), which are important for the proper functioning of the blood and nervous systems. It also contains vitamins E and K and small amounts of vitamins D and C, as well as easily digestible proteins. However, like other foods, milk can also contain various contaminants that can reduce its nutritional value. Nevertheless, in relation to blood cholesterol levels, milk is a rather neutral food and does not increase LDL cholesterol levels. Moreover, it tends to lower cholesterol levels and therefore does not increase the risk of cardiovascular disease (15-19).

For most of the population, milk can therefore be a suitable part of a balanced diet if consumed in moderation and as part of a varied diet. Caution is only advised for people with lactose intolerance or cow’s milk protein allergy.

References

• Nezdravé mléko: Pravda nebo mýtus? At: https://www.pharmapoint.cz/clanky/ nezdrave-mleko-pravda-nebo-mytus/#
• Mýty o mléce. At: https://www.vyzivaspol.cz/vyziva-a-potraviny-myty-a-realita/myty-o-mlece/
• https://www.denik.cz/zdravi/mleko-jidlo.html).
• https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/saturated-fats)
• https://bileminus.cz/pribehy-inspirace/8-nejvetsich-lzi-ktere-nam-rika-mlecny-prumysl
• USDA Cow’s Milk FDC_ID: 781084, 781093, 781089. Available online at: https://fdc.nal.usda.gov/
• Jensen, R. G., Ferris, A. M., Lammi-Keefe, C. J. 1991. The composition of milk fat. Journal of Dairy Science. 74, 3228–3243
• Moate P. J., Chalupa, W., Boston. R. C., Lean, I. L. 2007. Milk fatty acids. I. Variation in the concentration of individual fatty acids in bovine milk. Journal of Dairy Science. 90. 4730–4739
• MacGibbon, A. K. H., Taylor, M. W. 2006. Composition and structure of bovine milk lipids. Pages 1–42 in Advanced Dairy Chemistry. Vol. 2: Lipids. 3rd ed. P. F. Fox and P. L. H. McSweeney, ed. Springer, New York, NY.
• Wu X, Wang F, Chen M, Wang J, Zhang Y. Quantification of Free Short-Chain Fatty Acids in Raw Cow Milk by Gas Chromatography-Mass Spectrometry. Foods. 2023 Mar 23;12(7):1367. doi: 10.3390/foods12071367. PMID: 37048189; PMCID: PMC10093571.
• Ríos-Covián D, Ruas-Madiedo P, Margolles A, Gueimonde M, de Los Reyes-Gavilán CG, Salazar N. Intestinal Short Chain Fatty Acids and their Link with Diet and Human Health. Front Microbiol. 2016 Feb 17;7:185. doi: 10.3389/fmicb.2016.00185. PMID: 26925050; PMCID: PMC4756104.
• Bernard L, Delosière M, Hurtaud C, Imbert A, Viala D, Cebo C, Bonnet M. Polar lipids and proteins in milk fat globule membranes as players in spontaneous lipolysis in cow’s milk. Food Chem. 2025 Apr 15;471:142628. doi: 10.1016/j.foodchem.2024.142628. Epub 2024 Dec 31. PMID: 39788004.
• Conway V, Couture P, Richard C, Gauthier SF, Pouliot Y, Lamarche B. Impact of buttermilk consumption on plasma lipids and surrogate markers of cholesterol homeostasis in men and women. Nutr Metab Cardiovasc Dis. (2013) 23:1255–62
• Anto L, Warykas SW, Torres-Gonzalez M, Blesso CN. Milk Polar Lipids: Underappreciated Lipids with Emerging Health Benefits. Nutrients. 2020 Apr 4;12(4):1001. doi: 10.3390/nu12041001. PMID: 32260440; PMCID: PMC7230917.
• Vors C, Joumard-Cubizolles L, Lecomte M, Combe E, Ouchchane L, Drai J, et al. Milk polar lipids reduce lipid cardiovascular risk factors in overweight postmenopausal women: towards a gut sphingomyelin-cholesterol interplay. Gut. (2020) 69:487–501
• Nestel PJ, Mori TA. Dietary patterns, dietary nutrients and cardiovascular disease. Rev Cardiovasc Med. 2022 Jan 14;23(1):17. doi: 10.31083/j.rcm2301017. PMID: 35092209.
• Antunes IC, Bexiga R, Pinto C, Roseiro LC, Quaresma MAG. Cow’s Milk in Human Nutrition and the Emergence of Plant-Based Milk Alternatives. Foods. 2022 Dec 25;12(1):99. doi: 10.3390/foods12010099. PMID: 36613315; PMCID: PMC9818304.
• Nilsson Å, Duan RD, Ohlsson L. Digestion and Absorption of Milk Phospholipids in Newborns and Adults. Front Nutr. 2021 Aug 18;8:724006. doi: 10.3389/fnut.2021.724006. PMID: 34490332; PMCID: PMC8417471.
• Fontecha J, Calvo MV, Juarez M, Gil A, Martínez-Vizcaino V. Milk and Dairy Product Consumption and Cardiovascular Diseases: An Overview of Systematic Reviews and Meta-Analyses. Adv Nutr. 2019 May 1;10(suppl_2):S164-S189. doi: 10.1093/advances/nmy099. PMID: 31089735; PMCID: PMC6518146.

*This text has received support from the National Recovery Plan under project 1.4 CEDMO 1 – Z220312000000, Support for increasing the impact, innovation, and sustainability of CEDMO in the Czech Republic, which is financed by the EU Recovery and Resilience Facility.