Milk: Friend or Foe?

   

Are you a dairy lover like me, or do you avoid it, either for health reasons or because you simply don’t like it? The average Brit gets through nearly three pints of milk every week, but sales of milk have plummeted in the past ten years...

This may be partly explained by worries over the effect of high-fat dairy products on heart health, and partly because more and more of us suspect we’re intolerant to lactose or other substances found in milk. In contrast, sales of yoghurt increased by almost a quarter in the same ten years - perhaps as a result of the number of different brands now making health claims.

Milk Nutrition and Health

Milk and other dairy products are nutrient-dense. For the amount of calories they provide, they’re packed with more health-promoting nutrients than many other foods. Most of us know that they’re a good source of bone-building calcium. They’re also rich in protein and B vitamins, being vegetarians’ main source of vitamin B12, which is only found in animal products.

What's the difference between Skimmed Milk and Full-Fat?

Skimmed milk contains similar levels of vitamins, minerals and protein to full-fat milk, so you won’t miss out on calcium if you switch to a lower-fat variety. Whether you choose full-fat, semi-skimmed or skimmed milk, a 250ml glass meets around a third of your daily calcium and 15% of your protein needs. The only important difference is the fat and calorie content – a glass of skimmed milk contains 86 calories and no fat, while full-fat contains 156 calories and 9g of fat. That said, full-fat milk isn’t actually high in fat. If you’re trying to cut down on fat, it’s more important to limit cream, cheeses and butter.

Various large-scale studies have tried to identify the good and bad on how milk and dairy products affects aspects of health and fitness. Here are a few highlights...

Dairy and Your Muscles

Recent research has shown that milk can be just as effective for post-exercise recovery as much more expensive branded products. This is due to the fact that it contains both carbohydrate and protein for muscle recovery and plenty of fluid for rehydration. A glass of milk and a banana is a perfect natural post-workout snack.

Dairy and Diabetes Risk

Eating dairy products in moderation seems to help with weight loss - one study even found that cheese-eaters tended to have smaller waistlines! The same research also suggested that people who ate more dairy had a lower risk of diabetes. Whether this relates to the fact that they ate more high quality protein (and less sugary snacks) or is specifically because of nutrients in the milk is less clear.

How Dairy Affects Fertility

Anovulatory infertility is caused by failure of the ovaries to release an egg. After adjusting for weight and various lifestyle factors such as smoking, alcohol and caffeine intake, one large study found that women who drank whole milk daily or had a higher intake of full-fat dairy products overall were less likely to experience anovulatory infertility. In contrast, the more low-fat dairy products a woman ate, the more likely it was that she would experience the condition.  

Now, there are lots of other factors that could be at play - for example, low-fat dairy products such as yoghurts are often packed with sugar. The women who drank whole milk may have had a better diet overall. But it is an interesting result.

Ovary problems have also been linked to high levels of the milk sugar galactose in the blood, but this condition is rare.

Daily Allergies and Intolerances

Lactose intolerance is caused by the inability to produce enough of the enzyme lactase, which breaks down the sugars found in milk in our gut. It’s thought that certain populations have evolved to find milk easier to digest, given our long history of drinking it. That’s why lactose intolerance is much more common in Asian populations, who don’t traditionally drink milk, and tends to be rarer in people whose ancestors are from Northern Europe.  

That said, many people do suspect that they can’t tolerate dairy, and symptoms can vary from an immediate allergic reaction to an upset digestive system several days after drinking milk or eating cheese.  Some people also experience a feeling of ‘chestiness’ caused by excess mucus - although it’s suspected that this is caused by a protein called casein alpha-1 found in cow’s milk, the research on it isn’t clear. Dairy is also thought to be an eczema trigger.

If you suspect you have an intolerance to any foodstuff, it's a good idea to keep a food and symptom diary, as this can help you track whether patterns in flare-ups are linked to eating certain things.  You can then try cutting out those foods for 10 days and monitoring your symptoms. If there are noticeable changes, you’re probably right, but you should see a doctor or dietitian for a proper diagnosis. For more information on dairy intolerance visit Allergy UK. 

Should I switch to a different type of milk?

As goat’s milk contains a different type of casein, it can be a good alternative to try if you have been experiencing symptoms such as chestiness. Nutritionally, cow’s and goat’s milk are similar. In fact, 100g goat’s milk contain 4g protein compared to 3g in cow’s milk, and also contains 20mg more calcium. There are plenty of plant milk options available too - such as almond milk, rice milk, oat milk and soy products. If you switch to one of these, be aware that although they taste similar, they can be very different nutritionally. Most contain less protein than dairy, but you can get plenty of that from beans, nuts and grains. The main difference relates to their calcium content - so pick one that’s fortified or ensure you get plenty of calcium from other sources such as dark leafy greens, figs and almonds.

The bottom line is that milk is a healthy food that makes a great contribution to a balanced overall eating plan, but if you can’t or don’t want to drink it, you can still get its nutritional benefits from other foods.

REFERENCES

— Chavarro, J.E. et al. (2007) A prospective study of dairy foods intake and anovulatory infertility. Human Reproduction. 22(5): 1340-1347 Fumeron, F. et al. (2011) Dairy consumption and the incidence of hyperglycaemia and the metabolic syndrome. Diabetes Care. 34(4): 813-817 Haug, A., Hostmark, A.T. and Harstad, O.M. (2007) Bovine milk in human nutrition - a review. Lipids in Health and Disease. 6:25 doi:10.1186/1476-511X-6-25 Roy, B.D. (2008) Milk: the new sports drink? A review. Journal of the International Society of Sports Nutrition. 5:15 doi:10.1186/1550-2783-5-15 http://www.dairyco.org.uk/market-information/dairy-sales-consumption/uk-dairy-consumption/uk-dairy-consumption/