I am a big believer in keeping our diet based on foods that are as natural and unprocessed as possible. For me, the core foods (if we are happy to eat them) should be meat, fish, eggs, nuts, seeds, fruits and vegetables. I’m not a huge fan of milk, on the basis that I find it to be quite-common cause of problems related to food sensitivity. Either then lactose (sugar) or protein such as casein can cause problems here, and the protein seems to be a particular problem after pasteurization. By chance, I was talking to a receptionist yesterday and she told me how her longstanding itchy rash disappeared on the elimination of milk from her diet, but returned when she resumed milk.
While I’m not thrilled about pasteurized milk as a food, I’m much warmer to yoghurt. And this is primarily because the fact that it’s fermented does seem to partially digest its constituents, which makes it more digestible and less problematic. Also, for what it’s worth, there is at least some evidence linking yoghurt eating with improvements in terms of weight control.
It’s been theorised that this might have something to do with calcium. Consumption of calcium has been shown to paradoxically lower calcium level within fat cells, and this accelerates the process of lipolysis (breakdown of fat) Zemel MB, et al. Regulation of adiposity by dietary calcium. FASEB Journal 2000;14:1132-1138. There is considerable evidence linking higher intakes of calcium with reduced body fatness. Teegarden D. Calcium intake and reduction of fat mass. J Nutr 2003;133:249S–251S
Vitamin D has also been implicated in body weight regulation. In short, several studies have linked lower vitamin D levels with heightened risk of excess weight. Some of suggested, though, that this might be because the more fat someone carries, the more vitamin D can end up getting sequestered (transported to and stored in) in the fat cells. Mind you, there is a study which found that women with higher levels of vitamin D lost more weight than those with lower levels on a reduced calorie diet.
This background information may help provide some explanation of the results of a study published on-line this week in the American Journal of Clinical Nutrition. In this study, men and women were given one of two orange juices to drink on a daily basis [1]. One group received regular orange juice which containing 110 calories per serving (240 mls) and they were to consume 3 servings a day. The other group consumed ‘lite’ orange juice (containing artificial sweetener) containing 50 calories per serving (3 servings a day).
However, the study designed was actually more complex in that in each group, half of the people drank orange juice fortified with 350 mg of calcium and 100 IU of vitamin D, while the other half did not. In summary, therefore, there were four groups in this study:
- regular orange juice no fortification
- regular orange juice fortified with calcium and vitamin D
- lite orange juice no fortification
- lite orange juice fortified with calcium and vitamin D
The trial went on for 16 weeks.
Each of the study participants were assessed for a range of body measurements including body weight and waist circumference, and there were no significant differences between the groups here.
However, another assessment measured the amount of what is known as ‘visceral adipose tissue’ (VAT) – VAT is fat found in the abdomen and is particularly strongly linked with chronic diseases such as heart disease and type 2 diabetes.
Changes in VAT were not different between the regular- and lite-orange juice drinking groups (comparing groups 1+2 combined with groups 3 + 4 combined).
However, there were differences between the results obtained by those drinking fortified and non-fortified drinks. Group 2 lost more VAT than group 1, and group 4 lost more VAT than group 3.
It’s only one study, and this was also a study which was funded by The Beverage Institute for Health and Wellness which is part of the Coca Cola Company which supplied the product (Minute Maid). And just to be clear – I’m not a fan of fruit juices, principally because of the large sugar load they provide. However, the results of this study are, I think, interesting, and add to the body of evidence linking calcium and vitamin D with body weight and fat storage regulation.
References:
1. Rosenblum JL, et al. Differential effects of macronutrient content in 2 energy-restricted diets on cardiovascular risk factors and adipose tissue cell size in moderately obese individuals: a randomized controlled trial. Am J Clin Nutr 14 December 2011 epub ahead of print
