Milk And Dairy Products: Good Or Bad For Human Health? - Answers to the key questions
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Answers to the key questions
Key question 1: For the general consumer, will a diet with milk and dairy products overall provide better or worse health, and increase or decrease risk of major diseases and all-cause mortality than a diet with no or low content of milk and dairy products?
Consumption of dairy products is associated with an overall reduced risk of cardiometabolic diseases and some cancers, whereas only very few adverse effects have been reported (Fig. 1). Dairy products may therefore have the potential to reduce the burden of the most prevalent chronic diseases in the population and to substantially reduce the health care costs for society (109). Consumption of dairy products is part of the dietary recommendations in several nations, for example, Sweden, Denmark, and United States. A general recommendation to reduce the intake of dairy products in individuals who actually tolerate them may be counterproductive for health and could therefore increase health care expenses. However, more emphasis should be on the foods which dairy replaces in the diet. In addition, as most of the conducted meta-analyses are on observational data, residual confounding cannot be ruled out, and it is also possible that milk and dairy intake in these studies could be just a marker of diets of higher nutritional quality.
Key question 2: Is it justified to recommend the general lactose-tolerant population to avoid the consumption of milk and dairy products?
Fig. 1. Overall effect/association between dairy product intake and health outcomes. ↓ favourable effect/association; ↑adverse effect/association; → no effect/association.
In the Nordic countries, as few as 2% of the population has primary lactase deficiency and can be classified as lactose-intolerant individuals (110). Yet, most lactose-intolerant adults can tolerate one glass of milk or a scoop of ice cream. Cheeses have negligible lactose contents, and the lactose in yoghurt is digested more efficiently than other dairy sources due to the bacterial lactase present in yoghurt which facilitates lactose digestion (111). Therefore, fermented dairy products, that is, yoghurt and most cheeses (cottage cheese, as well as soft and hard cheeses), can be tolerated by lactose-intolerant individuals without symptoms (111, 112).
The same applies to cow’s milk protein allergy that typically occurs in 0.1–2.0% of children in the Nordic countries and Europe (113). Among children with verified cow’s milk-specific IgE who were re-evaluated 1 year after diagnosis, 69% tolerated cow’s milk at re-evaluation (114). Thus, the condition is generally seen to resolve in children. To warn the general population against dairy consumption based on rare milk allergies would be equivalent to warn against foods, such as peanuts or seafood due to the fact that a small subset of the population is allergic to these foods.
Key question 3: Is there scientific evidence to substantiate that replacing milk and dairy products with plant-based drinks will improve health?
Cow’s milk and plant-based drinks are not nutritionally comparable foods. As only a few studies have investigated the health effects of replacing cow’s milk with plant-based drinks and none have focused on commercially available drinks or on disease endpoints, the effect of this replacement can only be speculated on. There have, however, been individual cases reporting illness in children consuming low-protein plant-based drinks, but an evidence-based final assessment of the health value of plant-based drinks compared to cow’s milk must await more studies in humans.