Protein intake isn't the only thing that determines how much muscle and body fat people have. Canadian epidemiologists have discovered that the consumption of choline and betaine plays a significant role as well. According to their research, men and women who consume a relatively large amount of choline have several kilos more muscle mass and less body fat than men and women with little choline in their diet. Choline and betaine Choline, once thought to be a B vitamin, is found in egg yolks, meat, fish, shrimps and milk. Choline plays a role in the transport of fatty substances in the body, but is also a building block of cell membranes. In human experiments and animal studies, choline improves body composition. Betaine, a glycine metabolite, is found in beets, spinach and in a lot of grains. In the body, betaine acts as a methyl donor and helps cells retain water. Small studies indicate that betaine also improves body composition. Study Canadian epidemiologists, affiliated with Memorial University, analyzed data from 3214 residents of Newfoundland. That data had been collected in the Coding study. The researchers not only knew the diet of the study participants, but also had scans with which they could determine the participants' body composition. Results The more choline and betaine the study participants received through their diet, the less body fat they had. It was exactly the other way around for muscle mass. The more choline and beta were consumed by the participants, the greater was their muscle mass. Conclusion "The present study provides solid evidence for the first time, in the large Newfoundland population, that higher dietary choline and betaine intakes were associated with a more favorable body composition (lower body fat and higher lean body mass) in both women and men", the researchers write. "In addition, this favorable association was independent of age, gender, total calorie intake, physical activity level, menopausal status, smoking status, medication use, and alcohol consumption. The beneficial correlation for choline seems better than betaine." Source: PLoS One. 2016 May 11;11(5):e0155403.
This kind of highlights what I have been saying about a lot of studies, they are not well thought out or mainly come to conclusions already established. Also, this is a meta data study so simply reviewing other data to come to some conclusion - one that states a weak causation already established many times. Choline is found in eggs and animal fats. Betaine is found in many vegetables and certain whole grains. By the way Betaine is a precursor to choline so not sure why the study looked at both as though they were two different items. If you get plenty of choline you might not be worried about measuring betaine. Study finds that higher intake of animal fats and certain vegetables leads to better body compositions and the correlation is better for choline (animal fats). This study was already proven hundreds of times in keto, peleo, and whole food diet studies which focus on proteins, healthy fats and vegetables. So I think a few of us could have predicted the results before any $ was spent on this. Study does not indicate if while eating higher animal fats and vegetables/whole grains were they reducing processed foods and sugars. If so, why is a Ph.d. amazed that body composition improved on such a diet? Physical activity is left out or not fully incorporated. Interestingly enough, wheat germ/wheat bran is the highest source of betaine but Americna diets have mostly processed flour so it is stripped away in many cases and simply the high amounts of it in our diets does get many betaine. However, best sources are still spinach and beets and some original sprouted grains. So if the researches stated the hypothesis, it could have easily been answered before the meta data study. NOTE: In their correlation table the numbers seemed to range from insignificant to mild causation: The above numbers indicate that most of the results are a result of other factors than what was tested. Also note the conclusions from the authors: Another potential weakness in the present study is related to its cross-sectional design. Cross sectional study alone does not establish a cause effect relationship. Direct intervention studies or clinical trials with reasonable sample size and well matched subjects between treatment and control groups are warranted. Finally, although multiple factors, including socio-demographic characteristics, lifestyle habits, physical activities and energy intake were comprehensively adjusted in our analysis, genetic factors, dietary nutrient factors absorbed when consuming choline or betaine-rich foods and unknown or poorly measured factors could not be completely ruled out. This is why I read studies always skeptical and pour through them to spot all the flaws. Media uses studies to make headline generalizations but always be skeptical and read the statistical data yourself. This study sadly is quite lacking because it is not a first person study, it is a meta data analysis.