I promised the follow up to Part 1 of the Calcium questions...
First things first. Will milk help me lose weight?
Maybe… but hang on! Put down the cow and let’s dig a little into the manure…After some correlational studies showing a relationship between calcium intake and weight loss, this one researcher did a few trials showing that when compared to people on a calcium supplemented or placebo supplemented diet, those on a matched diet with dairy servings lost more weight, more body fat, and specifically more trunk (abdominal) fat over 6 months (1).
Holy Hysteria. The researcher patented his milk and weight loss claim, and enter in billions of ads with happy-looking size-0 women jamming yogurt down their throats and David Beckham pouring milk rivers down the crevasses in his abs. The peeps the researcher studied were obese individuals, not starving actresses or professional athletes. But still, who’s checking?!
Academic backlash: researchers slammed the studies for having too few people and pointed out that other studies have not found these results. Milk and body ads were then pulled from the market.
When did you make the mistake of thinking I care about this research? Tell me the bottom line!
A meta-analysis on randomized, controlled trials testing dairy products and weight loss attempted to resolve, or at least clarify, the controversy. Basically they found that if you just increased your dairy intake to reach your recommended daily intake of calcium but didn’t cut calories, weight-wise nothing would happen (your bones may love you though). However, if you were on a calorie-restricted diet AND consumed lots of dairy products, you may have a greater weight loss and higher reduction of fat mass and waist circumference than your buddy on a low-dairy calorie-restricted diet; this may be due to an increase in lean body mass that you get from the dairy protein (see previous chocolate milk blog!) (For other possible mechanisms, see footnote 2!)
Whatever! I am extremely socially unpopular when I eat dairy products. What if I eat spinach for my calcium?
The research described above was based on dairy product calcium consumption, not supplements. Milk is one of the best ways to absorb calcium for a number of possible reasons (3). It appears that the lactose does something to make it easier for calcium “get in” to your body, and the protein and fat in milk slow down the rate calcium rolls past the receptors. Milk often is Vitamin D fortified, which also enhances the absorption of the calcium.
But if you are lactose intolerant, there ARE other ways you can get your calcium. Spinach is not one of them (4). You absorb about 30% of the calcium found in milk, but only 5% from spinach. You need like 3 pounds of spinach to get the same amount of calcium in 1 cup of milk. Not only that, but the compound that binds with calcium making it less available to our body is called oxalate, and oxalate can effect the calcium in other sources consumed at the same meal! So, don’t drink your milk with your spinach. (Popeye knew what was up, and obviously spaced out his milk and spinach feedings, it just didn’t fit into the song.)
OK, so if I’m lactose intolerant, I’m screwed.
No. Kale (props given earlier here) continues to be the rockstar of our entire universe, and has less oxalate than spinach, and thus a better rate of calcium absorption. You only need about ¾ of a pound of kale to get the same amount of calcium as that in one glass of milk. Sardines or salmon canned with the bone are also good sources of calcium. (No, this does not mean you will be chewing on a bone like your puppy! The bones are soft and small enough you hardly notice!) Also, there is calcium-fortified soy milk, or even lactose-free milk and dairy products you can eat. Yogurt with active cultures and cottage cheese also are often well tolerated by lactose intolerant individuals (although you must experiment with this on your own).
Everyone I know says “don’t drink milk when you have a cold cuz it makes you produce more mucus.” Is everyone I know wrong?
Yes. Everyone you know is wrong.
Many researchers ran out and gave colds to people, gave some people milk and others water, and then measured their nasal drips (yuck). No diff. In another study, they gave some people a cold and then fed them soymilk, (which is non-dairy), but the researchers lied and said it was a dairy drink. The subjects began reporting massive amounts of snot, but it turned out it was all in their head…or rather it wasn’t in their head, but in their mind. :).
MS, RD, PhD
1. The three groups were as follows: 1. a low-calcium control diet with a placebo pill and only 400-500 mg of calcium; 2. Similar diet with 800 mg calcium supplement instead of a placebo; or 3. A high-dairy diet with 3 daily servings of dairy products and a placebo pill. All three diets were equal with regards to protein, fat, and carb content, and each allotted the subjects a 500 calorie per day deficit from their maintenance level, so they would be slated to lose about 1 pound per week.
The control guys lost about 6.5 % of their body weight, an average of 14.5 pounds; those in the high-calcium supplement diet lost about 8.6 % of their body weight, an average of around 18.9 pounds; and those in the high-dairy diet lost almost 11% of their body weight, an average of around 24.2 pounds. Fat loss was similar: low-calcium control guys lost 8.1 % of body fat, 11.6% for the high-calcium and 14.1% fat loss on the high-dairy diet.
Other than a small sample size, another big problem I had with this study was that the control diet group had more body fat to begin with; but the weight loss was calculated as percentage weight lost. Still, I think it would’ve been better to have balanced out the body weights across the three groups at the outset, rather than relying on pure randomization to control for this.
2. Why would dairy products enhance weight loss?
One idea is that calcium increases fecal fat excretion (which is exactly what it sounds like: how much fat you poop out). A meta-analysis of 13 studies showed that on average this increase was only about 2 -5 grams, which is like 18 – 45 calories…this is certainly nothing to start a parade over.
Because the effects seem to be tied to dairy food consumption, rather than calcium supplementation, other theories focus on the dairy products themselves. For one, milk is one of the best ways to absorb calcium, because the lactose appears to make it easier to “get in” to your body, and the protein and fat slow down the rate it rolls past the receptors. So the calcium in a supplement is quite different than that found in dairy. Secondly, milk protein contains a lot of leucine, a branch chain amino acid that may help maintain lean muscle tissue when losing weight. Finally, milk contains some bioactive compounds, one of which is linked to lowering blood pressure; this same compound also has an effect on fat cell metabolism. But these are just theories. Nobody really knows yet why dairy products seem to enhance calorie-restricted diets.
3. Another proposed mechanism is that casein, one of the milk proteins, prevents the formation of insoluble calcium salts which allows calcium to be free enough to bind to the receptors in our small intestine.
4. STILL EAT SPINACH!!
Studies on both sides of the calcium and weight loss argument:
Gunther, C.W., Legowski, P.A., Lyle, R.M., McCabe, G.P., Eagan, M.S., Peacock, M., & Teegarden, D. (2005). Dairy products do not lead to alterations in body weight or fat mass in young women in a 1-y intervention. American Journal of Clinical Nutrition, 81(4), 751-756.
Shahar, D.R., Schwarzfuchs, D., Fraser, D., Vardi, H., Thiery, J., Fiedler, G.M., Bluher, M., Stumvoll, M., Stampfer, M.J., Shair, I. (2010). Dairy calcium intake, serum vitamin D, and successful weight loss. American Journal of Clinical Nutrition, 92(5), 1017-1022.
The meta-analysis qualifying the milk and weight loss claims:
Abargouei, A.S., Janghorbani, M., Salehi-Marzijarani, M., Esmailzadeh, A. (2012). Effect of dairy consumption on weight and body composition in adults: a systematic review and meta-analysis of randomized controlled clinical trials. International Journal of Obesity, (in press).
Studies by Zemel, the researcher who patented the claim on calcium and weight loss:
Zemel, M.B., Thompson, W., Milstead, A., Morris, K., & Campbell, P. (2004). Calcium and Dairy Acceleration of Weight and Fat Loss during Energy Restriction in Obese Adults. Obesity Research, 12(4), 582-590.
Zemel, M.B., Richards, J., Milstead, A., & Campbell, P. (2005). Effects of calcium and dairy on body composition and weight loss in African-American adults. Obesity Research, 13(7), 1218-1225.
The Fecal Fat meta-analysis:
Christensen, R., Lorenzen, J. K., Svith, , C. R., Bartels, E. M., Melanson, E. L., Saris5, A. Tremblay, W. H., & Astrup, A. (2009). Effect of calcium from dairy and dietary supplements on faecal fat excretion: a meta-analysis of randomized controlled trials. Obesity Reviews, 10, 475-486.
For excitement on milk and mucus:
Farber JM, Finberg, L (1991). Milk effect on mucus production during upper respiratory tract infection. Journal of the American Medical Association, 266, 1289.
For a recent breakthrough on dairy and it’s potential to decrease inflammation:
Stancliffe, R.A., Thorpe, T., Zemel, M.B. (2011). Dairy attenuates oxidative and inflammatory stress in metabolic syndrome. American Journal of Clinical Nutrition, 94(2), 422-430.