Vegans have weaker bones. True or False?

The answer is ‘False’. Vegans do not have brittle bones.

Then why does this myth persist in society? Unfortunately, I don’t know the answer, I can only speculate. I was raised with the belief that milk makes strong bones and I had no reason to doubt my mother. I am not saying that I disagree with the statement that milk makes strong bones but this statement is no different than saying that oranges are a source of vitamin C. Oranges are not the ‘only’ source of vitamin C, they just happen to be ‘a’ source of vitamin C. If you don’t eat oranges, would you develop scurvy? Of course not, as long as you’re eating other fruits and vegetables.

From a very young age, we are taught that dairy products are essential for building strong bones, which is a smart way to advertise a product. If you make a product’s health impacts part of the elementary education system, it over time turns into a belief. The dairy industry has done just that, and not to mention, very successfully. Recently, I have noticed a new trend in dairy advertising in Canada i.e. endorsements from reputable non-profit charitable organizations such as the Colorectal Cancer Association of Canada, Osteoporosis Canada and the Heart & Stroke Foundation. From where I stand, these associations are advertising dairy on behalf of the Dairy Farmers of Canada. This is again a very smart advertising strategy, to advertise a controversial product through more socially acceptable and trusted channels. In my opinion, this is highly unethical and I have discussed the unethical nature of this practice at length in a previous post: Is it ethical to advertise dairy by non-profit associations?.

I am saddened to see that the public is falling for the successful advertising campaigns of the dairy industry when the science and evidence suggest that dairy may be harmful for human health. Science suggests that dairy doesn’t build strong bones and doesn’t prevent osteoporosis. I have never seen an advertisment saying ‘Eat more kale to prevent osteoporosis’. Have you?

Let’s get down to the science

I would like to share what Dr T. Colin Campbell, a scientist and an expert on animal protein, especially Caesin, has to say about dairy and osteoporosis. Osteoporosis is a bone disease and the cause for it is claimed to be inadequate intake of calcium. An excess rate of hip fractures is a reliable indicator of osteoporosis. But on the contrary, countries with the highest dairy consumption have the highest rate of hip fractures, as shown in recent studies[1]. Figure 1 below is a chart based on the epidemiology of hip fractures over the world as obtained from a study conducted in 2011[2]. Figure 2 below is a chart from Dr. Campbell’s book, The China Study and is based on a 1986 article published by Mark Hegsted in the Journal of Nutrition which shows that a higher intake of calcium was associated with higher risk of hip fracture[3]. I used the data provided by FAO to also chart a list of selected countries and their milk consumption in kg per capita in 2010 as shown in Figure 3.

Figure 1: Age-standardized hip fracture incidence per 100,000 in selected populations
Figure 2: Hip fracture incident in selected populations vs. daily calcium intake
Figure 2: Hip fracture incident in selected populations vs. daily calcium intake
Figure 3: Milk consumption per capita in selected populations

The correlation from these charts is very clear. The developed nations of the west are consuming more dairy and calcium, but still have the highest rates of hip fractures. So clearly, there is sufficient epidemiological evidence to prove that higher intake of calcium or dairy is not necessarily the only factor responsible for bone health. Only if biology were that simple. There are definitely other factors affecting bone health, but what are they?

Two variables have been identified by science that affect bone health and throw a wrench in this hypothesis of more calcium and dairy equals strong bones.

1. Excess Animal Protein Intake

In 1992 researchers discovered that there is a strong association between animal protein intake in diet and bone fracture rate for women in different countries[4]. Further research has revealed the phenomenon of acidosis i.e. the increased acid load on the body as a result of a high protein diet and the resulting excessive acid leaching calcium from bones and muscles leading to bone and muscle loss[5,6,7]. This opinion is supported by the observation that calcium content in urine increases after a high protein diet[8,9,10]. This phenomenon is also observed in people following a low carb-high protein diet similar to Atkins or Paleo, where the calcium levels in the urine increase significantly[11]. Dr. Campbell also states “A high ratio of vegetable to animal protein consumption was found to be impressively associated with a virtual disappearance of bone fractures”[12,13]. Recent studies go further to suggest that high dietary acid load is more likely to result in diabetes and systemic hypertension and may increase cardiovascular risk[14,15]. These studies can’t be ignored, while the dairy industry still suggests that we should be consuming more of its products to build strong bones and teeth. These studies raise a serious question about the claims made by the dairy industry regarding the protein-rich dairy foods.

But I am also not suggesting that dietary protein should be avoided to prevent osteoporosis because there are studies suggesting that there is a minimum level of dietary protein that is required to maintain bone health and prevent osteoporosis[16,17]. So metaphorically, obesity and anorexia are both unhealthy states and finding a balance is the key. In my opinion more research is required in this field to unveil the truth but the data and studies mentioned above definitely bust the myth that “vegans have brittle bones” or “more dairy and calcium equals strong bones”.

2. Excess Calcium Intake

Yes, that’s correct, excess calcium intake may cause osteoporosis. This theory is explained really well by Dr. Campbell in his book, The China Study. Dr. Campbell states,”Mark Hegsted, a Harvard professor, believed that excessively high intakes of calcium consumed over a long time impair the body’s ability to control how much calcium it uses and when. Under healthy conditions, the body uses an activated form of vitamin D, calcitriol, to adjust how much calcium it absorbs from food and how much it excretes and distributes in the bone. Calcitriol is considered a hormone; when more calcium is needed, it enhances calcium absorption and restricts calcium excretion. If too much calcium is consumed over a long period of time, the body may lose its ability to regulate calcitriol, permanently or temporarily disrupting the regulation of calcium absorption and excretion. Ruining the regulatory mechanism in this way is a recipe for osteoporosis in menopausal and post-menopausal women. Women at this stage of life must be able to enhance their utilization of calcium in a timely manner, especially if they continue to consume a diet high in animal protein. The fact that the body loses its ability to control finely tuned mechanisms when they are subjected to continuous abuse is a well-established phenomenon in biology”[18].

This theory explains what we observe throughout the world that countries consuming the most amount of calcium have the highest rate of hip fractures as seen in Figure 2 above.

Pro-Dairy Research

What about all the pro-dairy studies? There is a lot of research out there that supports the dairy industry’s claim[19,20,21]. Most of this research is focused on bone mineral density (BMD) and the associated risk of osteoporosis. I find this approach reductionist. It makes more sense to focus on diet and lifestyle and associated osteoporosis risk rather than focusing on a single biomarker such as BMD. This is scientific reductionism and I personally don’t believe in it. In Dr. Garth Davis’ terms, “it is like looking at a pixel rather than the entire picture”.

A lot of this pro-dairy research focused on BMD is contradictory to measures of overall health, well-being and vitality. For example, high BMD is related to increased risk of osteoarthritis[22] and breast cancer[23,24]. Another confusing fact is that eastern developing countries that have lower calcium and dairy intake and lower hip fracture rate also have lower BMD[25,26,27]. So in my opinion, BMD is not the right measure for osteoporosis risk.

So I would like to reiterate that more research is required before we can start making claims about positive impacts of dairy on bone health. I have never seen any other animal on this planet drink milk in adulthood for the purpose of building strong bones. And for skeptics who believe plants don’t have sufficient calcium, I would suggest you go tell that to a gorilla who chews on fruits, leaves and seeds all day long. Some arguments don’t need science to settle, they just need common sense.

Conclusion

Unfortunately, dairy is high in both calcium and protein. Based on the best information we have today, both of these ingredients in excess are actually harmful for bone health. Only further research can demystify the controversy around dairy and reveal the truth about the impacts of dairy on human health. So what are we supposed to do in the meanwhile to minimize risk of osteoporosis? Here is what Dr. Campbell recommends:

1) Stay physically active.
2) Eat a variety of whole plant foods. Beans and leafy vegetables are a rich source of calcium.
3) Avoid animal foods including dairy.
4) Avoid refined carbohydrates and processed foods.
5) Minimize your salt intake.

There is also a great video from Dr. Michael Greger on his website here.

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