Milk is often presented as a cornerstone of a healthy diet, a message reinforced from childhood through marketing and educational campaigns. However, a doctor and gut health specialist is challenging this long-held belief, asserting that milk is primarily for babies and not an essential nutrient for adults.
Dr. Alan Desmond contends that the idea of milk being crucial for adult bone health, while a successful marketing strategy, is not strongly supported by scientific evidence. He explains that human breast milk is a high-energy food designed for infant growth, containing lactose, a sugar digested by an enzyme called lactase. After weaning, the body's production of lactase typically declines, leading to lactose intolerance in a significant portion of the adult population worldwide.
For individuals experiencing symptoms like gas, bloating, cramping, abdominal pain, or diarrhea after consuming cow's milk, Desmond states that this is a normal biological response. He emphasizes that the inability to digest milk comfortably is the human default for most adults, not a personal failing.
Regarding bone health, Desmond points out that while milk is a source of calcium, large-scale studies and meta-analyses have not demonstrated a significant reduction in fracture risk associated with higher milk intake. He further notes that calcium is a mineral absorbed by plants from the soil and then passed to cows through their diet. Abundant alternative sources of calcium for adults include leafy green vegetables like kale and spring greens, as well as beans and nuts. For example, a serving of cooked spring greens or kale can provide a substantial amount of calcium, and calcium-set tofu can offer a similar amount to a glass of milk. Many plant-based milk alternatives also now match cow's milk in calcium content per serving.
Beyond calcium, Desmond highlights that bone density also relies on vitamin D, primarily synthesized by the skin through sun exposure or obtained via supplements, and on weight-bearing exercise. Activities such as brisk walking, running, dancing, and resistance training are essential for maintaining bone strength throughout life.
While fermented dairy products like yogurt are often easier to digest and can provide protein and calcium, Desmond questions their status as a superfood. He notes that despite claims of boosting the gut microbiome, typical yogurts contain only a few strains of bacteria and lack fiber, a key nutrient for gut microbes. Studies examining the direct impact of adding yogurt to the diet without other lifestyle changes have not shown meaningful weight loss.
Kefir, another fermented dairy drink, may contain a wider variety of microbes, but research has not yet conclusively linked its consumption to significant health improvements in areas like blood sugar or inflammation. In contrast, studies on healthy, high-fiber, low-meat diets have shown substantial positive impacts on the microbiome, cholesterol levels, fasting glucose, and markers of chronic inflammation, regardless of dairy content.
Desmond concludes that while dairy products can be part of a healthy diet, they are not essential. He advocates for a diverse, calcium-rich diet, regular exercise, adequate vitamin D, and evidence-based nutritional guidance, suggesting that a diet free from dairy is a perfectly valid and healthy choice. His views are further detailed in his book, "What Your Doctor Isn’t Telling You About Food."