Obesity affects one-third of adults in the United States and is approaching $100 billion annually in healthcare costs. Efforts aimed at decreasing obesity have focused primarily on treatment approaches designed to manage energy balance through calorie restriction (CR) and exercise. The role of micronutrients in energy balance remains understudied.
Epidemiological and cross-sectional investigations began to identify calcium intake as a dietary constituent that was inversely related to body weight and body fat levels. One hypothesis generated postulates that low calcium intake leads to increased intracellular calcium levels due to a change in circulating calcium-regulating hormones, particularly 1,25-dihyroxyvitamin D and parathyroid hormone. High intracellular calcium levels, in turn, act to reduce lipolysis and increase lipogenesis in adipocytes. Increasing dietary calcium is thought to inhibit these effects and facilitate fat loss.
The role of parathyroid hormone and 1,25 dihydroxy vitamin D in the regulation of body weight and the magnitude of the calcium-body weight relationship remain unclear. In light of this controversy, it is unclear how prominent a position calcium should play in the treatment of obesity. Additionally, at present, there are no data on the long-term weight loss efficacy of following a high-calcium diet beyond 6 months.
A study was performed to determine whether the weight loss and body composition of subjects on a calorie restricted diet with and without high levels of dairy calcium intake would differ at 3-, 6-, and 12-month time points. Fifty-four overweight and obese adults were recruited to participate. Eligibility criteria included age between 18 years and 60 years, BMI between 25 kg/[m.sup.2] and 34.9 kg/[m.sup.2], current calcium consumption = 500 mg/day, current dairy product consumption < 1 serving per day, no medical problems that would contraindicate CR and nonsmokers.
Interested individuals participated in four screening sessions. By phone, they were initially screened for baseline calcium intake, availability, medical history, BMI, and usual dairy calcium intake. Subjects were excluded if they consumed more than one serving of dairy products per day. If eligible, they were invited to attend an orientation session where the study was described in more detail. All subjects participated in a screening history and physical.
Screening visit 3 involved an interview where subjects were asked to report on their motivations, expectations, barriers, eating behaviors, food aversion, and allergies. They also completed the Beck Depression Inventory and the Taylor Manifest Anxiety Scale. At screening visit 4, food records were visually assessed for total calcium consumption by scanning for servings of dairy and high-calcium foods. Those eligible were randomized to one of two conditions: CR + dairy (CR + D; n = 25) or CR (n = 29).
Subjects participated in a 12-month behavioral weight loss program. The weight loss treatment program focused on the modification of eating and exercise habits through the use of behavioral strategies and self-management skills.
Subjects were given prescribed menus, grocery lists, and recipes specific to their dietary condition. Calorie goals were formulated to represent a 500 kcal/day restriction from baseline levels. The treatment programs differed only in the diets prescribed. The CR+D group was provided menus that included three to four servings of dairy products per day (milk, yogurt, and cheese) with a dairy calcium intake goal of 1200 mg/day to 1400 mg/day. The diet was structured to provide 10% to 15% of calories from protein, 55% to 65% carbohydrate, 30% fat, and 25 grams of fiber per day. Participants in the CR condition were provided menus, grocery lists, and recipes that included approximately one serving of dairy per day with a total calcium intake goal of 400 mg/day to 500 mg/day.
There were no significant differences between groups at baseline. At 12 months, weight and body fat loss were not significantly different. Subjects in the CR versus CR plus D conditions lost 9.6 [+ or -] 6.5 versus 10.8 [+ or -] 5.9 kg (p = 0.56) and 9.0 [+ or -]3.8 versus 10.1 [+ or -] 3.6 kg body fat (p = 0.37).
These finding suggest that a high-dairy calcium diet does not significantly improve weight loss beyond what occurs with a standard calorie restricted diet.
Increased calcium does not impact weight loss
About 33 per cent of adult citizens of The United States are affected by obesity. This condition approaches 100 billion dollars annually in healthcare costs. Efforts made in order to at reduce obesity among the citizens have concentrated mainly on treatment approaches intended to manage energy balance through calorie restriction (CR) and physical activity. The role of micronutrients in energy balance is still not researched sufficiently.
Both epidemiological and cross-sectional examinations started to recognize calcium intake as a dietary component that was inversely connected with body weight and body fat levels. One of the hypotheses generated a suggestion that little calcium intake results in increased intracellular calcium levels caused by a change in circulating calcium-regulating hormones, especially 1,25-dihyroxyvitamin D and parathyroid hormone. High intracellular calcium levels, in turn, proceed to decrease lipolysis and raise lipogenesis in adipocytes. Increasing dietary calcium is believed to inhibit these effects and make fat loss much easier.
The role of parathyroid hormone and 1,25 dihydroxy vitamin D in the control of body weight and the scale of the calcium-body weight relationship are still not exactly clear. In light of this controversy, it is not clear how important the role that calcium should play in the treatment of obesity. In addition, currently there are no precise data concerning the long-term weight loss effectiveness of following a high-calcium diet beyond six months.
Special research was conducted in order to find out whether the weight loss and body composition of subjects on a calorie limited diet with and without high levels of dairy calcium intake would vary at 3-, 6-, and 12-month time points. Fifty-four adult citizens that are overweight and obese were recruited to take part in the research. Eligibility criteria included age between 18 years and 60 years, BMI between 25 kg/[m.sup.2] and 34.9 kg/[m.sup.2], current calcium consumption = 500 mg/day, current dairy product consumption < 1 serving each day, lack of any medical problems that would contraindicate CR and nonsmokers.
Interested persons attended four screening sessions. At first, they were screened by means of the telephone for baseline calcium consumption, availability, medical history, BMI, and typical dairy calcium consumption. Subjects were excluded if they consumed more than one serving of dairy products per day. If the candidates appeared to be eligible, they were invited to take part in an orientation session where the research was described in more detail. All participants took part in a screening history and physical.
Screening visit 3 involved an interview where participants were asked to report on their motivations, expectations, barriers, eating habits, food aversion, and various allergies. They also completed the Beck Depression Inventory and the Taylor Manifest Anxiety Scale. At screening visit 4, food records were visually evaluated for total calcium intake by scanning for servings of dairy and high-calcium foods. The participants that appeared to be eligible were randomized to one of two conditions: CR + dairy (CR + D; n = 25) or CR (n = 29).
Subjects took part in a 12-month behavioral weight loss program. The weight loss treatment program concentrated on the alteration of eating and exercise habits by means of using various behavioral strategies and self-management skills.
Subjects received prescribed menus, grocery lists, and recipes precise to their dietary condition. Calorie objectives were formulated to stand for a 500 kcal/day limitation from baseline levels. The treatment programs varied merely in the diets recommended. The CR+D group was provided with the menus that comprised three to four servings of dairy products each day (milk, yogurt, and cheese) with a dairy calcium intake objective of 1200 mg/day to 1400 mg/day. The diet was structured in such a way to provide 10 per cent to 15 per cent of calories from protein, 55 per cent to 65 per cent carbohydrate, 30 per cent fat, and 25 grams of fiber daily. Participants in the CR condition were given menus, grocery lists, and recipes that comprised approximately one serving of dairy per day with a total calcium intake objective of 400 mg/day to 500 mg/day.
There were no important dissimilarities between groups at baseline. At twelve months, weight and body fat loss were not considerably varied. Subjects in the CR versus CR plus D conditions lost 9.6 [+ or -] 6.5 versus 10.8 [+ or -] 5.9 kg (p = 0.56) and 9.0 [+ or -]3.8 in comparison with 10.1 [+ or -] 3.6 kg body fat (p = 0.37).
These results indicate that a high-dairy calcium diet does not considerably improve weight loss beyond what happens with a standard calorie restricted diet.
