Dairy products have always received attention in health circles for one reason or another. They are our most important source of calcium and a valuable source of quality protein. Low fat dairy products are associated with a number of improved health outcomes and more recently milk products have shown potential as recovery drinks for athletes. We should be getting at least 2 portions of dairy every day, 3 if you are pregnant or lactating. A portion is roughly 1 cup of milk or 175ml of yoghurt. This provides us with our DRI for calcium as well as some good protein, as well as a source of energy from fats and carbohydrates. Dairy also has a few other components of interest for our health.
Calcium is important for bone health, nerve transmission and heart and other muscle function. Interestingly a high calcium intake is associated with a reduced prevalence of overweight and obesity. Other sources of calcium are limited but include rhubarb, spinach and fish (when the soft bones are included). The calcium content is pretty much the same regardless of the fat content of milk, so low fat and skimmed have as much as full cream milk. Calcium is water soluble and thus remains behind despite the removal of any fat.
The protein is of good quality in milk products and is a mix of casein and whey. These two proteins are isolated for nutritional products and also used to increase protein content of food items. They are of high biological value meaning we absorb and use a a high percentage of the protein and the mixture gives us both “fast acting” (whey) and “slow acting” (casein) protein which is of interest in the post exercise time frame as well as for benefits on satiety. Milk gives us about 3.4g of protein per 100ml.
The fat content is a mixture of saturated and unsaturated fats but the amount will naturally vary according to your choice of full cream, low fat or skimmed. Full cream milk has on average 3.5g of fat per 100ml compared to 2g and 0.4g for low fat and skimmed version respectively. Not much of a difference if you think about it! Low fat is always a good option though if you have a fair amount of milk or yoghurt or if you are following a calorie restricted diet. Unless the situation calls for significant restrictions I never recommend skimmed milk unless someone is comfortable drinking it or prefers the taste. Personally I don’t! As the amount of fat reduces, the proportion of other nutrients naturally increases to take up the space that used to be fat, so the protein, carbohydrate and other nutrient levels increase marginally.
Milk also contains a fatty acid called conjugated linoleic acid (CLA) which gained interest as a weight loss supplement, anti-cancer compound and “preventor” of heart disease. Research is not conclusive as to the effect of food sources of CLA though and there may be some side effects to the use of CLA as a dietary supplement. Interestingly the CLA content in milk and meat from grass fed cows (and other ruminants) can be up to 5 times higher than that from their grain fed cousins. Similarly the fat profile is usually better in that there is a lower total fat content and higher proportions of monounsaturated and omega 3 fats. Unfortunately the quantity of milk is less in these grass fed animals and thus industry is less likely to opt for it, but if you can find it buy the grass fed option!
The carbohydrate content of milk is purely in the form of lactose, a type of sugar. Some people are intolerant to it as they do not produce the enzyme to digest lactose and this leads to gut discomfort. All forms of fresh milk in South Africa have similar carbohydrate content of around 4.8g per 100ml. This, along with the fat content of milk, allows it to be a good source of energy. Add to that the protein content and milk is a balanced food and the reason why animals and humans produce it to allow their young to grow!
Milk is also a good source of the B vitamin riboflavin which is an important part of carbohydrate, fat and protein metabolism and also supports antioxidant protection.
For athletes milk has received the thumbs up from a number of research papers as a possible whole food recovery drink. Post exercise consumption of a sweetened milk product provides a good source of carbohydrate and protein to assist glycogen repletion and muscle repair. Milk has also been shown to assist rehydration and is a good source of sodium and potassium. Choose that Steri-Stumpie or Yogi-Sip as your next post workout drink! Aim for 500ml and a fruit or a few jelly babies and you have a good recovery snack.