Are dairy products good for your health or linked to issues such as heart disease, food intolerance and weight gain? Stephanie Osfield investigates.
Dairy has had a bad rap in recent years. The resulting misconceptions have led a growing number of New Zealanders to needlessly reduce or cut out foods such as milk, yoghurt and cheese. A New Zealand study found a third of people questioned about their milk intake drank less than a cup of milk a day, and nearly 10 per cent of young people didn’t drink any milk. This means they’re at higher risk of poor bone health and osteoporosis.
So, what’s the deal with dairy? Is full fat healthy or is it bad for the heart? And does it affect your weight?
The dairy debate
For decades, we’ve been encouraged to consume reduced-fat dairy foods. Full-fat dairy was not recommended, as it contains saturated fats that are believed to increase the risk of heart disease.
A review by the University of Reading, England, the University of Copenhagen and organisations in the Netherlands looked at 29 studies that investigated the effect of dairy intake on heart disease. It found that eating 200g of dairy a day, from high-fat or low-fat products, milks, yoghurt, fermented products or cheese didn’t increase your risk of cardiovascular disease or coronary heart disease. But for people whose body mass index was more than 25 (overweight or obese), choosing low-fat dairy products did slightly reduce the risk of mortality from heart disease.
Although the effect of dairy on cholesterol and heart disease is still being investigated, choosing low-fat dairy foods will still help you to reduce your daily energy intake, which can help maintain a healthy weight.
It’s a myth that you can’t absorb calcium by consuming low-fat milk, as full-cream, low-fat and trim milk have fairly similar amounts of calcium. Another popular myth, according to dietitian Lisa Renn, is that low-fat milk has added sugar.
“In fact, the reason it tastes a little sweeter is because the removal of the fats makes the taste of the natural sugars more obvious,” Ms Renn says.
However, sugar or sweetener may be added to other reduced-fat dairy foods such as custard and yoghurt. When choosing low-fat yoghurt or other dairy, look for options that have 10g or less of sugar per 100g. Or try natural low-fat yoghurt and add fresh fruit or spices.
Milk and muffin tops
“There is a mistaken belief that dairy foods are fattening when, in fact, studies show they can help people lose weight,” Ms Renn says. “The mouthfeel and creamy texture make them very satisfying. They are a good source of protein, which makes you feel full for longer, reducing hunger and kilojoule intake between meals.”
Foods such as yoghurt and cheese also have a low GI, which means they don’t cause a big spike in blood-glucose levels or insulin after you eat them. “I often recommend low-fat dairy foods, such as yoghurt, a small trim latte or hot cocoa, or a small, low-fat fruit smoothie, as a healthy, filling snack,” Ms Renn says.
The high protein levels found in dairy foods are also beneficial for maintaining a healthy amount of muscle. In a study at Canada’s McMaster University, overweight women were put on a weight-loss diet combined with daily exercise. Those who consumed higher amounts of dairy lost more fat from all over their body, particularly their abdomen, as well as gaining greater muscle strength and density.
This lowering of body fat may be the reason why consumption of dairy is linked to a reduced risk of developing type 2 diabetes. Research from Lund University in Sweden has shown that eating yoghurt and cheese can help to reduce the risk of type 2 diabetes by as much as 20 per cent.
Building strong bones
Calcium is a pivotal mineral for building and maintaining strong bones. Around 99 per cent of the calcium in our body is stored in our bones (the rest is used to help our heart, muscles, blood and nerves work properly). Calcium combines with other minerals to give our bones strength and structure. The calcium we eat, and most of it comes from dairy foods, is used to keep our bones strong, reducing the risk of fractures and osteoporosis. New Zealand healthy eating guidelines recommend adults have at least two servings a day of dairy products. Good choices include a glass of milk or calcium-fortified milk alternative (250ml), a pottle of yoghurt (125g-150g) or 2 slices of cheese (40g).
Milk allergy vs lactose intolerance
Milk allergy occurs when the immune system has an adverse reaction to the protein in milk, which can lead to a serious response called anaphylaxis. “This can affect breathing and can be fatal if not treated with an EpiPen and medical help,” nutritionist Rosemary Stanton says. “Those with an allergy to milk protein need to avoid all dairy products, including in processed foods. Fortunately, most affected children grow out of milk allergy by the age of about four.”
Some people are intolerant to milk’s natural sugar, lactose. “This intolerance occurs when the body lacks an enzyme called lactase, needed to digest the lactose,” Dr Stanton explains. “The lactose then passes to the large intestine, where it can cause such symptoms as bloating, pain and diarrhoea.”
That doesn’t mean dairy should be avoided altogether. “Lactose intolerance is not an allergy,” she says. “Most cheeses have minimal lactose and the bacteria in yoghurt break down some of the lactose, reducing the amount that reaches the intestine. This is why people with lactose intolerance can usually have small amounts of dairy foods, including up to a cup of milk a day, without symptoms.”
Although we don’t know how many Kiwis are avoiding cows’ milk and other dairy products, it’s likely numbers are growing as increasing numbers of people choose to follow vegan diets or avoid milk products because of gastrointestinal symptoms, for example as part of the low-FODMAP diet.
“The problem is that dairy foods may not be the cause of these symptoms,” Ms Renn says. “They could be triggered by stress worsening irritable bowel disease, or an intolerance to something else, such as the natural chemicals in food, called amines and salicylates.
“Hydrogen breath tests can check whether you are lactose intolerant, but it is also a good idea to see a dietitian, who can help clarify if you really do have an intolerance to dairy foods. That way, you will ensure you are not needlessly missing out on the important, health-boosting nutrients in dairy foods.”
Help… I can’t stomach dairy!
If you are affected by lactose intolerance, dietitian Catherine Saxelby says to make sure you choose a milk substitute that is fortified with calcium. Here are the most common options:
- Soy milk has a calcium, protein and kilojoule profile most like cow’s milk.
- Rice milk is usually made from brown rice, but tends to have a high glycaemic index (GI) and only a small amount of protein.
- Oat milk is high in fibre but low in protein. Unless it’s fortified, it can also be low in calcium. Oat milk should be avoided if you’ve got coeliac disease.
- Almond milk can be low in protein.
- Coconut milk is very high in saturated fat, so should not be consumed in large amounts.