Time To Ditch Dairy?

For the most part, low-fat dairy products have been recommended as part as a healthy diet for quite some time now.  However, it is now becoming popular to eliminate dairy from ones eating regime! What is wrong with dairy? I’ll explore the reasons people are going dairy-free and highlight the supporting research.

Concern for Dairy – Fact or Fiction?

1.  Dairy causes cancer
2.  Dairy is net acid producing
3.  Dairy is detrimental to bone health
4.  May be a trigger for acne
5.  We didn’t evolve drinking milk and most populations can’t digest milk

The Evidence:

1. Dairy causes cancer: SEE BELOW

• Milk and dairy products contain micronutrients and several bioactive constituents that may influence cancer risk and progression. However, little is known about the potential effect of these.
• Dairy products are a complex group of foods and composition varies by region, which makes evaluation of their association with disease risk difficult. For most cancers, associations between cancer risk and intake of milk and dairy products have been examined only in a small number of cohort studies, and data are inconsistent or lacking.
• Meta-analyses of cohort data available to date support an inverse association between milk intake and risk of colorectal and bladder cancer and a positive association between diets high in calcium and risk of prostate cancer.
• CONCLUSION: In general, dairy intake has not been linked to cancer, however high calcium intake has been in some studies. Be cautious against extra calcium supplementation if you already consume dairy.  How could too much calcium promote prostate cancer? The theory: The active form of vitamin D—which we get mostly from sunlight—may protect the prostate. And calcium lowers levels of active vitamin D in the blood. Not all studies see a link between calcium and prostate cancer. And most men never reach the “too-much-calcium” range. Calcium may really be only a concern for men who get more than 2,000 mg s a day. One glass of milk delivers about 300 mg.
  (Lampe, 2011)

2. Dairy is net acid producing: FALSE

• This is based on the idea that the protein and phosphate in milk and dairy products make them acid-producing foods which cause our bodies to become acidified, promoting diseases of modern civilization.
• However, scientific evidence does not support this. Milk and dairy products neither produce acid upon metabolism nor cause metabolic acidosis, and systemic (entire body) pH is not influenced by diet. Measurement of an acidic pH urine does not reflect metabolic acidosis or an adverse health condition. Alkaline diets alter urine pH but do not change systemic pH.
  (Heaney, 2001; Fenton, 2011).

3.  Dairy is detrimental to bone health: FALSE

• Some authors have suggested that dairy products are not helpful and perhaps detrimental to bone health because higher osteoporotic fracture incidence is observed in countries with higher dairy product consumption.
• Observations of higher dairy product intake in countries with prevalent osteoporosis do not hold when urban environments are compared, likely due to physical labor in rural locations. North America does not have higher rates of osteoporosis when you compare across sedentary populations. Other factors across populations should also be considered: quantity of milk consumption, differing Vitamin D status and genetics.
  (Fenton, 2011)

4. May be a trigger for acne: INCONCLUSIVE 

• For years there has been interest in a diet and acne connection. Prospective, cohort studies were done by Adebamowo and colleagues in 2006 and 2008. These studies suggested a correlation, not a cause-and-effect relationship between dairy and acne. More research is needed to confirm whether specific foods and/or dietary constituents have a direct effect on acne. To date there are no randomized controlled trials investigating the relationship between frequent dairy or milk consumption and acne incidence

 5. We didn’t evolve drinking milk and therefore most populations can’t digest milk: SEE BELOW

• In mammals, lactase, the enzyme that breaks down the milk sugar lactose, is normally down-regulated after weaning, but at least five human populations around the world have independently evolved mutations regulating the expression of the lactase-phlorizin-hydrolase gene…in other words a handful of populations have adapted to tolerate dairy by breaking down lactose.
• It was thought that since we didn’t evolve drinking milk, this gene started to get expressed as we started consuming milk, therefore needing to break down lactose. However, work by Kruttli (2014) revealed that the frequency of lactase persistence in medieval Germany (72%) is similar to that found today in Germany and Austria (71–80%).
• CONCLUSION: some populations had the ability to break down lactose, long before dairy entered the human diet (around 9000 years ago).  Some Caucasian populations had the tools to drink milk long before we did and this wasn’t a result of the introduction of milk to our diets.

THE BOTTOM LINE: Before you go ahead and eliminate dairy from your diet, get to know the facts. Some can’t tolerate much dairy, and that’s fine – just ensure you are consuming other calcium-rich foods (instead of supplements), such as leafy greens and plant-based milks. However dairy shouldn’t be eliminated due to the fact that it is acid-producing or that it is detrimental to bone health – these are not facts. Calcium could potentially be linked to harm if consumed in excess, but this is almost always through supplementation. Supplement with caution!