Dairy products are among the richest sources of calcium, the primary mineral found in bones.
For this reason, health experts often recommend including dairy products in your daily diet.
However, many people question whether dairy is truly necessary.
This review, based on scientific evidence, explores the topic in detail.
The Evolutionary Perspective on Dairy Consumption
The idea that adults “need” dairy in their diet is somewhat questionable from an evolutionary standpoint.
Humans are unique in consuming milk beyond infancy and drinking the milk of other species.
Before domestication, milk was likely a rare treat primarily reserved for infants. It is uncertain how much hunter-gatherers actually sought the milk of wild animals.
Since milk consumption was probably uncommon among adults throughout most of human history, it’s reasonable to believe that humans obtained sufficient calcium from other dietary sources (1Trusted Source).
That said, although dairy isn’t essential for everyone, it can still be beneficial—particularly for individuals who do not get enough calcium from other foods.
Understanding Osteoporosis
Osteoporosis is a progressive condition characterized by the weakening of bones, with a gradual loss of bone mass and minerals.
The term itself describes the disease well: osteoporosis means “porous bones.”
Multiple factors contribute to osteoporosis, many of which are unrelated to nutrition, such as physical activity and hormonal changes (2Trusted Source, 3Trusted Source).
Women, especially postmenopausal women, are at a higher risk of developing osteoporosis. The disease greatly increases the likelihood of fractures, which can severely impact quality of life.
The Importance of Calcium
Bones not only provide structure but also serve as the body’s primary calcium reservoir, a mineral vital for many bodily functions.
Calcium levels in the blood are tightly regulated. When dietary calcium is insufficient, the body draws calcium from bones to maintain necessary blood calcium levels for critical functions.
Calcium is also continuously lost through urine. If dietary intake doesn’t replace this loss, bones lose calcium over time, leading to reduced density and increased fracture risk.
Debunking the Myth That Protein Harms Bone Health
Despite dairy’s rich calcium content, some claim that its high protein level might promote osteoporosis.
The reasoning is that protein digestion increases blood acidity, prompting the body to leach calcium from bones to neutralize this acid.
This concept is the foundation of the acid-alkaline diet, which suggests eating foods with an alkalizing effect while avoiding acid-forming foods.
However, scientific support for this idea is minimal.
In fact, dairy’s high protein content is beneficial. Research consistently shows that higher protein intake improves bone health (4Trusted Source, 5Trusted Source, 6Trusted Source, 7Trusted Source).
Besides protein and calcium, dairy is also rich in phosphorus, and full-fat dairy from grass-fed cows contains vitamin K2.
Protein, phosphorus, and vitamin K2 all play important roles in maintaining bone health (8Trusted Source, 9Trusted Source).
Mixed Results from Observational Studies
Some observational studies indicate that increased dairy consumption has no significant impact or may even negatively affect bone health (10Trusted Source, 11Trusted Source).
However, most research shows a clear link between higher dairy intake and a lower risk of osteoporosis (12Trusted Source, 13Trusted Source, 14Trusted Source).
It’s important to note that observational studies detect associations but cannot establish cause and effect.
Randomized Controlled Trials Provide Clearer Evidence
Randomized controlled trials (RCTs) are the gold standard for determining cause and effect in nutrition studies.
These experiments divide participants into groups, with one group receiving an intervention (like increased dairy intake) and the other group maintaining their usual diet.
Many RCTs have examined dairy and calcium’s impact on bone health and mostly conclude that dairy or calcium supplementation is effective.
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Childhood: Dairy and calcium promote increased bone growth (15Trusted Source, 16Trusted Source, 17Trusted Source).
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Adulthood: Dairy slows bone loss and enhances bone density (18Trusted Source, 19Trusted Source, 20Trusted Source).
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Elderly: Calcium supplements improve bone density and reduce fracture risk (21Trusted Source, 22Trusted Source, 23Trusted Source).
RCTs consistently demonstrate dairy’s positive effects on bone health across all age groups.
Milk fortified with vitamin D appears even more effective in strengthening bones (24Trusted Source).
However, calcium supplements should be used with caution, as some studies link them to a higher risk of heart attacks (25Trusted Source, 26Trusted Source).
It’s generally better to obtain calcium from dairy or other calcium-rich foods like leafy greens and fish.
Final Thoughts
Bone health is influenced by many lifestyle factors.
Calcium intake through diet is one of the most crucial.
To support or maintain bone health, ensuring adequate calcium consumption is essential.
In modern diets, dairy contributes a significant portion of people’s calcium.
Although many other foods contain calcium, dairy remains one of the most effective sources available.