Monday 2nd November 2009Back when I was in primary school, I remember that all pupils were provided with a bottle of full fat milk as it was deemed 'good for you' both by our teachers, parents and doctors. After all we are aware that cows milk provides us not only with calcium, but also with Vitamin D and many other beneficial nutrients. So milk is good for us...isn't it?
A growing number of consumer advocates and scientists don't think this is necessarily the case. They question the long-held wisdom of regular milk consumption, and some of these people even believe milk poses substantial health risks.
What's at the bottom of this backlash? Is there any truth to what the critics are saying, or is it just a storm in a carton?
How Milk Has Changed.
Some of the controversy surrounding milk lies in the way commercially available cow's milk has changed over recent years. In general, milk consists of water, fat, protein, lactose, minerals, vitamins, and enzymes. But the exact composition of milk depends on what cows eat, their cycle of lactation, the number of lactation's, and how the milk is processed. Today's commercial milk-production techniques can significantly modify the end product, changing it from its natural form into something quite different.
For example, most commercially produced milk undergoes pasteurization to destroy bacteria that may be harmful to health. However, some people claim that raw, unpasteurized milk tastes better and is more nutritious than the pasteurized variety.
Out to Pasture
Does pasteurization affect the nutritional value of milk?Yes. Although pasteurization kills potentially dangerous bacteria, such as listeria, E. coli, and salmonella, it also kills off harmless and useful bacteria, such as lactobacillus acidophilus, and active enzymes that help with digestion and absorption of nutrients. Some studies also suggest that pasteurization reduces the amount of vitamins B1, B6, B12, and C contained in milk.
However, this reduction in nutrients is not significant and the risks associated with consuming raw milk outweigh the benefits.
Home on the Grain
Is the milk from grain-fed cows less healthful than the milk of grass-fed cows?Yes. Almost all of the long-chain polyunsaturated fatty acids (PUFAs) in milk are the result of what the cows eat; when cows graze on grass and mixed greens, it improves the fat composition of their milk, equalizing the ratio of omega-6 to omega-3 fatty acids. This ratio is believed to be ideal for human health because it helps raise good cholesterol, lower triglycerides, and reduce inflammation. Research suggests that a cow raised grazing on its natural diet of fresh pasture also has five times more conjugated linoleic acid (CLA), a cancer-fighting fat.
By replacing a cow's grass diet with grain, the ratio of the essential fatty acid in the milk is greatly altered. Milk from commercially raised cows whose feed contains blood meal or bone meal has a more detrimental fatty acid composition and contains little, if any, CLA.
It’s not easy to find milk products from dairies that raise cows on open pastures. Some organic dairy cows are grass-fed, but not all. Nevertheless, consumers are buying organic milk and dairy products in record numbers.
Can Milk Be A Weight Loss Booster?
Recent research touts the benefits of milk when it comes to losing weight. Does including three servings of milk in the daily diet help the average person lose weight?No. Although some studies suggest a possible role, it is not a simple case of drink milk, lose weight. In the most widely publicized studies, which were funded by the National Dairy Council, obese people who were on a calorie-restricted diet that included three to four dairy servings per day increased their rate of weight loss compared to obese people who consumed fewer dairy products.
However, the population size of these studies was too small and too specific to extend the claims about weight loss to the general population. Larger randomized trials on the dairy–weight loss connection reveal that adding dairy to the diet without restricting calories has no effect on, or actually may increase, body weight.
Although dairy may not solve your stalled weight loss program, drinking milk may help you get more results from your exercise routine. Milk provides a complete protein, which means it offers all of the essential amino acids or building blocks of protein. Dietary protein helps build and repair muscle tissue and can serve as a source of energy during high endurance exercises such as running, cycling, and other aerobic exercise.
Good for getting your muscles strong, yes. But what about strong bones? Calcium found in milk has long been touted as the key to preventing osteoporosis, a debilitating disease characterized by low bone mass and deteriorating bone tissue.
Bone Strengthener?
Is drinking milk daily the only key to protecting adults against osteoporosis?No. Although your body does need calcium to build and maintain bone strength—especially when you're young—it is only one of several habits that help keep bones strong. Other important habits that may play an even more important role include getting plenty of vitamin D, not smoking, and regular physical activity, especially weight-bearing exercises.
Recent studies suggest that, as an adult, getting the recommended amount of vitamin D is as important as getting enough calcium because the body needs vitamin D to absorb calcium from food or supplements.
Although milk contains calcium and is fortified with vitamin D, there are other sources of these nutrients. You could get the calcium you need by eating lots of dark-green leafy vegetables, beans, and calcium-fortified products, or by taking enough supplemental calcium to reach your targeted intake. You can generally get enough vitamin D from fatty fish and occasional exposure to sunlight—for example, 10 to 15 minutes in the sun a few days a week during non peak hours without sunscreen
Some experts question whether milk should be recommended at all for osteoporosis prevention.
For example, some studies reveal that the incidence of bone fractures—the most tangible consequence of osteoporosis—is very low in countries where average daily calcium intake is as low as 300 milligrams per day.
Some milk critics claim that osteoporosis incidence is actually higher in countries that consume more daily servings of milk because milk leaches calcium from bones, making them weaker.
Although too much animal protein will leach calcium from bones, the amount that is leached depends on the ratio of calcium to protein intake in your diet. Because so many foods are fortified with calcium, it is unlikely that drinking milk in reasonable amounts would cause leaching of calcium from bone.
So although milk can be part of the prevention picture for osteoporosis, it doesn’t have to be.
But there are other diseases besides osteoporosis that concern the older population. For example, cancer has recently surpassed heart disease as the leading cause of death for people of a certain age in the United States.
Cancer Fighter?
Have studies revealed that drinking milk may help lower a person's risk of developing colorectal cancer?Yes. An analysis of data from 10 different studies revealed that milk consumption reduced the risks of rectal cancer and cancer of the distal colon, which is the portion of the colon closer to the rectum. People who drank over 8 ounces of milk per day, the equivalent of about 250 grams of calcium, had a 15% reduction in rectal cancer and distal colon cancer risk compared to people who drank less than a couple 8-ounce glasses per week. And milk reduced the risk of colon cancer more than other calcium-laden foods such as yogurt or cheese, suggesting something particular about milk produced the effect.
However, the data on such positive associations between milk consumption and colon cancer risk come from studies that were conducted before rBGH was used in milk. Additional studies are needed to determine whether today’s milk shows the same results.
The Beauty Factor Conclusion
Overall, there is no evidence to justify claims that modern milk has any special power to improve any specific aspect of health.
Any positive effects from drinking milk are usually explained by an elevated intake of calcium or vitamin D, nutrients that can easily be found in sufficient quantities from other sources. In addition, the potential health risks posed by modern milk production techniques need further research.
If you choose to keep milk on your menu, organic milk might be a healthier choice than commercial milk given current processing practices. But if you decide to skip dairy products altogether, rest assured that there is no reason to believe milk is a necessity, as long as you eat a balanced and varied diet that includes other sources of calcium, vitamin D, and protein.
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