We have all been raised with the idea that milk is a requirement for healthy bones but this belief has little evidence to back it up. Decades ago the joint FAO/WHO (Food and Agriculture Organization of the United Nations/World Health Organization) Expert Consultation on Vitamin and Mineral Requirements in Human Nutrition pointed out that there exists a calcium paradox in that hip fracture rates are greater in developed countries where calcium intake is high than in developing countries where calcium intake is much lower (1,2). Many studies have backed up the existence of such a paradox.
Higher milk intake has not shown protection from bone fractures
A 2011 meta-analysis of prospective cohort studies found no association between increasing milk intake and hip fracture risk (3).
This supported an earlier meta-analysis that included both prospective cohort studies and randomized controlled trials and reported no association between calcium intake and hip fracture risk in men and women (4).
The Harvard Nurses’ Health Study followed more than 72,000 women for 18 years and found no difference in the risk of fractures between women drinking two or more glasses of milk a day and those drinking one glass or less a week (5).
The Harvard Health Professionals Follow-up Study found that people who drank one glass of milk or less per week had no greater risk of breaking a hip or a forearm than those who drank more than two and a half glasses of milk a day (6).
A 2015 analysis of 44 randomized controlled trials and observational studies showed that dietary calcium intake is not associated with fracture risk and that there is no evidence that increasing calcium intake from ingestion of milk or other dairy foods prevents fractures (7).
Milk intake may actually be detrimental to bone health
Large-scale studies have found that consuming dairy is more likely damaging than beneficial for bone health and that higher milk intake may in fact be linked with increased risk of bone fractures (8,9).
A 2014 study from Sweden involving over 100,000 men and women looked at the associations between milk consumption and bone fracture or death. This observational study found that the rates of heart disease, cancer and early death increased in women with each daily glass of milk consumed. Women drinking three or more glasses of milk a day had almost twice the rate of death and a 60% increased risk of hip fracture compared to women drinking less than a glass of milk a day. Men also showed higher death rates but no change in fracture rate. In this study oxidative stress was associated with milk intake in both women and men. Researchers suspected the milk sugar, D-galactose, was the likely cause of all of these effects (8).
Drinking milk as teenagers has long been credited with creating a higher peak bone mass and contributing to stronger bones in later life. However, a 2014 study with more than 96,000 participants found that the more milk consumed by males in their teenage years, the greater the number of bone fractures they experienced as adults. Results showed a 9% increase in fracture risk for every daily glass of milk ingested as a teenager (9).
Further studies showed that the boost in bone mineral density during teenage years is lost after about seven years and so the expected benefit of stronger bones into old age never materializes (10).
Why does drinking milk not reduce bone fractures?
Calcium is an essential nutrient and is vital for bone health. However, scientific investigations are now discovering the importance of where that calcium comes from. The calcium that is found in milk is unfortunately accompanied by other substances that seem to produce negative effects on bone strength.
In a nutrition advisory, WHO indicated that present scientific data suggests that protein, and animal protein in particular, is the factor outweighing the potentially positive effect of calcium intake from milk. For instance, the dairy protein in milk along with its sodium content have been associated with increased excretion of calcium in the urine. The same effect happens after eating animal-sources of protein from meat or eggs. Calcium levels in the blood are tightly controlled because the movement of calcium across cell membranes affects many fundamental body processes such as muscle contraction and nerve cell activity (11). With any loss of calcium in the urine, levels of calcium in the blood begin to fall, and the body immediately increases its rate of absorption of calcium from the diet. If this measure is insufficient to bring blood calcium back into a healthy range, for instance with a diet insufficient in calcium, the needed calcium is taken from the bones (12). The result can be loss of bone mass and higher fracture risk.
Strong associations have been found between the amount of animal protein in the diet and rate of hip fracture. A review encompassing 34 published studies in 16 countries found that higher dietary animal protein was directly associated with higher bone fracture rates in females. This association could not be explained by dietary calcium or total caloric intake (2).
Other research points to D-galactose, a monosaccharide sugar that is abundant in milk, as a possible culprit interfering with any possible fracture protection that might be realized from drinking milk. This sugar is associated with increased oxidative stress and inflammation and studies in animals link ingestion of D-galactose with early aging (8,13).
Dietary choices that support healthy bones
We have associated milk with bone health for so long that many people are reluctant to banish dairy from their diet. In 2015, researchers recruited 82 young, non-obese adults and placed them into three different dietary groups according to their self-reported eating habits. The three diet groups were omnivores (who ate both animal- and plant-sourced foods); lacto-ovo vegetarians (who ate no meat but included eggs and dairy in their diet); and vegans (who ate only plant-sourced foods and no meat, dairy or eggs). BMD of the subjects was measured through whole body DXA scans. (BMD is Bone Mineral Density – the amount of bone mineral in the bone tissue which is a direct indicator of bone strength and fracture risk.) Information on calcium excretion was obtained from 24-hour urine specimens. BMD results in this study showed no significant difference among the three groups. Researchers concluded that well-balanced plant-based diets provide adequate nutrients for bone health (14).
Other studies have examined the BMD of older participants. Researchers compared 105 lifelong, vegan Buddhist nuns with 105 similar-aged, meat-eating women from Vietnam. In spite of the much lower intake of calcium and protein in the nuns, both groups had similar BMDs (15).
Investigations have also looked specifically diet and fracture risk. The 2014 Singapore Chinese Health Study analyzed the effect of two dietary patterns on the risk of hip fracture. In this study over 63,000 men and women were studied for almost 10 years. Participants were placed in either a meat-based diet group or a vegetable-fruit-soy diet group according to their self-reported eating habits. Investigators found that those eating within the vegetable-fruit-soy group suffered fewer hip fractures. Additionally, the higher the consumption of fruits, vegetables and soy, the greater the protection, with those eating the highest amounts of vegetables, fruit and soy showing a 21% to 34% lower risk of hip fracture compared to those eating the lowest amounts. Participants eating within the meat-based group had no protection against hip fracture (16). This coincides with earlier research illustrating that Asian women, whose bone mineral density is generally lower that that of Western women, have a significantly lower rate of hip fracture. This effect is thought to be due to the lower intake of animal-sourced foods in Asia as well as their customary higher intake of fruits, vegetables and soy (17).
In addition a Canadian retrospective study looked at dietary patterns and fracture risk. Two dietary patterns were identified that showed quite different effects on bone health. The first was a nutrient-dense diet high in fruit, vegetables and whole grains; the second was an energy-dense diet high in meats, desserts, soft drinks, potato chips and French fries. The nutrient-dense pattern was associated with lower fracture risk in women. The energy-dense pattern was not related to fracture risk (18).
Saying goodbye to dairy
It is clear that milk is not a necessary ingredient for healthy bones and might even be detrimental. It is becoming increasingly clear that moving away from animal-sourced foods and embracing plant-based sources is not a risk for decreased BMD. On the contrary, higher amounts of fruits and vegetables in the diet can reduce risk of bone fractures.
There are numerous non-dairy foods that are excellent dietary sources of calcium without the unhealthy ingredients that are a part of the dairy package. These include foods such as broccoli, kale and other dark leafy greens, beans, tofu, figs and non-dairy calcium-fortified beverages (19). There is no need to worry about missing nutrients from avoiding milk. Everything you need for healthy bones can be acquired from eating a variety of whole plant-sourced foods.
2 Abelow, B.J., Holford, T.R., Insogna, K.L. Cross-cultural association between dietary animal protein and hip fracture: a hypothesis. Calcif Tissue Int. 1992 Jan;50(1):14-18.
3 Bischoff-Ferrari, H.A., Dawson-Hughes, B., Baron, J.A., Kanis, J.A., Orav, E.J., Staehelin, H.B., Kiel, D.P., Burckhardt, P., Henschkowski, J., Spiegelman, D., Li, R., Wong, J.B., Feskanich, D., Willett, W.C. Milk intake and risk of hip fracture in men and women: a meta-analysis of prospective cohort studies. J Bone Miner Res. 2011 Apr;26(4):833-839.
4 Bischoff-Ferrari, H.A., Dawson-Hughes, B., Baron, J.A., et al. Calcium intake and hip fracture risk in men and women: a meta-analysis of prospective cohort studies and randomized controlled trials. Am J Clin Nutr. 2007; 86:1780–1790.
5 Feskanich, D., Willett, W.C., Stampfer, M.J., Colditz, G.A. Milk, dietary calcium, and bone fractures in women: a 12-year prospective study. Am J Public Health. 1997 Jun; 87(6):992-997.
6 Owusu, W., Willett, W.C., Feskanich, D., Ascherio, A., Spiegelman, D., Colditz, G.A. Calcium intake and the incidence of forearm and hip fractures among men. J Nutr. 1997; 127:1782–1787.
7 Bolland, M.J., Leung, W., Tai, V., Bastin, S., Gamble, G.D., Grey, A., Reid, I.R. Calcium intake and risk of fracture: systematic review. BMJ. 2015; 351: h4580.
8 Michaëlsson, K., Wolk, A., Langenskiöld, S., Basu, S., Lemming, E.W., Melhus, H., Byberg, L. Milk intake and risk of mortality and fractures in women and men: cohort studies. BMJ 2014; 349
9 Feskanich, D., Bischoff-Ferrari, H.A., Frazier, A.L., Willett, W.C. Milk consumption during teenage years and risk of hip fractures in older adults. JAMA Pediatr. 2014 Jan;168(1):54-60.
10 Matkovic, V., Goel, P.K., Badenshop-Stevens, N.E., Landoll, J.D., Li, B., Ilich, J.Z. et al. Calcium supplementation and bone mineral density in females from childhood to young adulthood: a randomized controlled trial. Am J Clin Nutr. 2005 Jan;81(1):175-188.
12 Mangano, K.M., Walsh, S.J., Kenny, A.M., Insogna, K.L., Kerstetter, J.E. Dietary acid load is associated with lower bone mineral density in men with low intake of dietary calcium. J Bone Miner Res. 2014 Feb;29(2):500-506.
13 Lai, K., Elsas, L.J., Wierenga, K.J. Galactose Toxicity in Animals. IUBMB Life. 2009 Nov; 61(11): 1063–1074.
14 Knurick, J.R., Johnston, C., Wherry, S.J., Aguayo, I. Comparison of correlates of bone mineral density in individuals adhering to lacto-ovo, vegan, or omnivore diets: A cross-sectional investigation. Nutrients. May 11, 2015; 7(5): 3416-3426.
15 Ho-Pham, L.T., Nguyen, P.L., Le, T.T., et al. Veganism, bone mineral density, and body composition: a study in Buddhist nuns. Osteoporos Int. 2009 Dec;20(12):2087-2093.
16 Dai, Z., Butler, L.M., van Dam, R.M., Ang, L.-W., Yuan, J.-M., Koh, W.-P. Adherence to a Vegetable-Fruit-Soy Dietary Pattern or the Alternative Healthy Eating Index Is Associated with Lower Hip Fracture Risk among Singapore Chinese. J of Nutrition. April, 2014; 144(4): 511–518.
17 Anderson, J.J. Plant-based diets and bone health: nutritional implications. Am J Clin Nutr. 1999 Sep;70(3 Suppl):539S-542S. Review.
18 Langsetmo, L., Hanley, D.A., Prior, J.C., Barr, S.I., Anastassiades, T., Towheed, T., Goltzman, D., Morin, S., Poliquin, S., Kreiger, N. Dietary patterns and incident low-trauma fractures in postmenopausal women and men aged ≥50 y: A population-based cohort study. Am J Clin Nutr. Jan. 1, 2011; 93(1):
19 Pennington, J.A.T. Bowes and Church’s Food Values of Portions Commonly Used. 16th Edition, Philadelphia, J.B. Lippincott, 1994.
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