Article extracted from abstract and executive summary of research conducted at Johns Hopkins university’s Bloomberg School Of Public Health – Principal Investigator: Lawrence J. Cheskin, MD, FACP, Associate Professor, Health, Behavior & Society
The American diet, and increasingly the global diet, is strikingly high in energy density, yet often low in nutrient density. This increase in energy density, as well as calorie and fat intake, is a major driver of the recent increase in obesity worldwide.
Mushrooms are a low-calorie source of nutrients and have the added advantage of being used as substitutes for high-calorie, low nutrient-density foods such as meats. The feasibility and effectiveness of using mushrooms as substitutes for meat in the diet were studied in a controlled clinical trial at the Johns Hopkins Weight Management Center, a program of the Johns Hopkins Bloomberg School of Public Health, in Baltimore, MD.
This study specifically examined the potential of white button mushrooms as a tool for controlling body weight and treating obesity.
Participants in this study were recruited via advertisements, which were placed in local newspapers (Baltimore Sun, City Paper), as well as via flyers posted at local sites (supermarket bulletin boards, e.g.) and on campus. The study included a total of 209 adult men and women aged 18 and older with a body-mass index between 25-40 (overweight to obese), who were interested in losing weight and reported a willingness to substitute white button mushrooms for beef in their daily meals over the course of one year. The final analysis included 74 participants, for a drop-out rate of 65% after 12 months.
Participants agreed to be randomly assigned to one of two diets: one based on the USDA Food Guide Pyramid with a reduced calorie level individualized to their needs (standard diet), or the standard diet plan enhanced by substituting some meat dishes with mushrooms (mushroom diet).
Participants assigned to the standard diet were instructed on various methods to improve their diet, without the recommendation of mushroom substitution. Both groups received vouchers for local grocery stores in the amount of $6 per week. Participants assigned to the mushroom diet were required to substitute mushrooms (8oz) for meat at three different meals each week, while participants assigned to the standard diet were required to eat 90+% lean ground beef for three meals each week. Purchases were confirmed by the return of the receipt the next visit. Subsequent food vouchers were not given unless proof of mushroom/meat purchase from the previous week was furnished.
Participants underwent a 6-month weight loss period, followed by a 6-month weight maintenance period. They were given diet counseling and were instructed on making healthy food choices. Since the study was a single-blinded clinical trial, the study counselor was not aware of the diet group to which the participant was randomized. The participants were instructed to not mention their diet assignment to the investigator conducting the counseling.
Baseline and follow-up measures of body weight, blood chemistries, and measures of oxidative stress, inflammation, and immunity were collected.
Results were that the people following the mushroom diet lost an average of 7 pounds, or 3.6% of their starting weight, and lowered their BMI, waist size, and percent body fat significantly, while people following the standard diet lost an average of only 2.2 pounds or 1.1% of their starting weight. There were also significant improvements in blood pressure, triglycerides, fasting blood glucose, and cholesterol on the mushroom diet.
Following initial weight loss, people following the mushroom-rich weight maintenance diet maintained that loss well. Those who completed the full 12-month study period still weighed 7 lbs less than before starting their diet plan. HDL-cholesterol levels also showed significant improvement at 12 months compared to baseline levels. Blood pressure and serum triglycerides also were significantly improved at this time point. It is well known that maintenance of lost weight can be more challenging than even the initial task of losing weight, so the high degree of weight maintenance seen in the mushroom group is very promising.
Further, consuming a mushroom-enriched diet led to improvements in measures of inflammation and oxidative stress, known to be markers of increased risk for cardiovascular disease, cancer, and other leading health problems.
One aspect of the findings are worthy of note: The drop-out rate, at 65% after 12 months, is high, but not out of line with other long-term weight loss studies. It is revealing that the rate of drop-out is no difference between the mushroom-consuming group and the standard diet group, indicating that even people asked to eat mushrooms regularly for an entire year were no more likely to drop out of the study than people with no dietary requirements to eat mushrooms regularly. This speaks well for the long-term acceptability of regular mushroom consumption.
The cost of dieting using mushrooms as substitutes for high fat, high energy density meats, and other foods would be quite favorable as well. Future work could calculate these cost savings and benefits.
The results of this work demonstrate that a diet using mushrooms as a substitute for high-calorie foods such as meats can be helpful for adults seeking to control their weight and improve blood pressure, cholesterol, and measures of oxidative stress and inflammation. This message can be a driver of increased interest in the use of mushrooms by the general public.