Dairy: Healthy choice or health risk?

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  • There is a lot of debate on the pros and cons of dairy consumption.
  • In some studies, milk consumption has been linked to various diseases, such as diabetes and cancer.
  • Deutsche Welle takes a look at the latest science to get to the bottom of these issues.

With the rise of non-dairy alternatives cropping up in the supermarket aisle, you’d be inclined to think that dairy has been cancelled and the industry is slowly collapsing. 

From almond to coconut, soya, oat and rice milk, the demand for dairy alternatives has shifted from being solely available in health stores to the shelves of local supermarkets. According to market research, the global dairy alternatives market is expected to reach $26 billion this year.

READ MORE | How much milk and dairy should we consume?

But dairy has long been promoted as a superfood, particularly in the Western world. In fact, the nutrition guidelines in many countries list dairy products as an essential part of a healthy diet. At the same time, there are many countries where people eat few dairy products and yet remain healthy, notes Deutsche Welle (DW).

And then some claim consuming milk leads to illness, including diabetes and even cancer.

So what’s the deal with dairy? Mira Fricke, science editor at DW, takes a look at the latest scientific studies to set the record straight.

Mother’s milk

There’s no debate that mother’s milk, in humans or other mammals, is the number one source of nutrition. This milk is packed with vitamins and minerals, as well as fats and proteins, to help babies grow.

For babies, it’s clearly a superfood. However, after the first year of life most adults lose the ability to digest lactose (the sugar found in milk), says Fricke. 

READ MORE | Mother's milk a miracle medicine for mom and baby

Around 65% of the world’s population is lactose intolerant during their adult years, leading to digestive issues such as bloating or diarrhoea, but there are strong regional differences.

For example, just 5% of Northern Europe’s population is lactose intolerant, while in some Asian and African countries, more than 90% of adults are unable to digest lactose.

There are genetic reasons for that, notes Fricke. It’s likely that the first farmers who settled in Europe developed the ability to digest lactose, especially in places where milk was essential to their survival, she says.

READ MORE | How potato milk measures up against other plant-based milk alternatives

“Resources were more limited, and people living in these European countries had to feed from resources that were there, and cattle was a good nutrition resource throughout the year,” says professor Christina Ellervik, a doctor at Harvard Medical School who researches the effects of dairy products on health.

The authors of a 2009 study wrote that this then “surfed on a wave of population expansion that followed the rapid co-evolution of milk tolerance and dairy farming.”

Despite the digestive issues for some people, milk is still a good source of nutrients. Harvard Health notes that dairy products such as milk, yoghurt, cheese and cottage cheese are all good sources of calcium, which helps maintain bone density and reduces the risk of fractures.

But what about the other health effects of consuming milk?

Does dairy cause pimples?

Maybe. In several studies, researchers have found a link between dairy consumption and acne, particularly in teenagers.

“Milk actually increases another hormone, called the insulin-like growth factor, which promotes growth in general, but it could be involved in the growth of many things, [including] acne,” says Ellervik.

Multiple studies show that people who consume dairy products have a higher risk of acne, although it remains to be confirmed whether it is milk that causes it. 

Does milk cause heart disease and diabetes?

The thought behind this theory is that the fat in dairy products damages blood vessels, leading to heart and circulatory illness.

But science suggests otherwise. Canadian scientist, professor Jean-Philippe Drouin-Chartier at Laval University, tells DW that researchers have found no difference in risk between people with high intakes of dairy compared to those with low intakes.

READ MORE | Plant-based milk products: What you need to know before making the switch

The latest research shows that dairy products do not cause heart disease or diabetes. Says Fricke: “On the contrary, several studies show that consuming milk can reduce the risk of diabetes.”

The type of dairy product could play a role 

A large study involving more than 280 000 people in the US found that people who ate yoghurt had a lower risk of diabetes. Yoghurt is fermented and contains bacteria that support the microbiome in the gut, and this could explain its positive effect, says DW.

Finally, does milk increase your cancer risk?

A few studies, particularly on prostate cancer, have suggested a link between milk consumption and cancer risk.

However, there is no evidence yet that milk is actually the cause of this type of cancer, says DW. The same growth factor that may contribute to acne is seen as a possible reason for the link, but various studies have yet to confirm this, they add.

READ MORE | Lactose intolerant? Here are a few alternatives to dairy

Asked whether dairy products should be avoided, Nobel prize winner professor Harald zur Hausen tells DW that he would be careful about saying that, as dairy products do play an important role in the human diet. “I would caution against any panic,” he says.

The bottom line: you can lead a healthy life with or without dairy - what’s important is what else you eat in addition to them.

Says Vasanti Malik, nutrition research scientist with the Harvard T.H. Chan School of Public Health: “... keep in mind that eating a well-balanced diet that includes plenty of green leafy vegetables and nuts can better help you get the calcium and protein you need rather than relying too much on dairy.”


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