Dangerous abdominal fat
Obesity-related metabolic disorders such as dyslipidemia and insulin resistance are risk factors for cardiovascular disease, especially in older people. In this context, visceral adipose tissue, better known as abdominal fat, plays a decisive role. Abdominal fat consists of cells that lie under the muscle layer in the abdomen and surround the internal organs. In fact, visceral adipose tissue serves as an energy reserve in the absence of food, but it also has numerous negative properties. Among other things, it can increase the release of inflammatory and other messenger substances and promote vascular-damaging blood lipids. People with too much abdominal fat often suffer from high blood pressure and have an increased risk of cardiovascular disease, fatty liver and type 2 diabetes. Although weight loss is considered an effective means of reducing abdominal fat, long-term success is often limited. In older people, who per se have an increased risk of cardiovascular disease, weight loss can even be detrimental to the muscles. The guidelines for older adults therefore recommend moderate calorie restriction and maintaining muscle mass.

A comparison of two diets
Against this background, scientists from DIfE and Charité – Universitätsmedizin Berlin have investigated the effects of a specific dietary pattern on visceral adipose tissue and the cardiometabolic risk profile within the “NutriAct” competence cluster of nutrition research. For the three-year NutriAct nutrition study, 502 men and women aged between 50 and 80 were randomly assigned to an intervention group or a control group. The intervention group followed the NutriAct dietary pattern with a high proportion of monounsaturated and polyunsaturated fatty acids, predominantly vegetable proteins and fiber. They received specially prepared food and took part in eleven small group sessions over a 12-month period, including nutrition, cooking and lifestyle advice. The control group, on the other hand, ate according to the standard recommendations of the German Association for Nutrition and received nutritional counseling three times and some free conventional food for a year.

MRI examination shows clear results
To analyze the visceral adipose tissue, a magnetic resonance imaging (MRI) examination was carried out on a subgroup of 300 test subjects at the beginning and after 12 months of nutritional intervention. This measurement method is much more precise than the commonly used waist circumference measurement and is considered the gold standard. The MRI examination showed a significant reduction in visceral adipose tissue in the intervention group, while there were no changes in the control group. “This reduction was largely mediated by the increased intake of polyunsaturated fatty acids and was accompanied by an improvement in the cardiometabolic risk marker LDL cholesterol. The altered intake of monounsaturated fatty acids, proteins and dietary fiber does not appear to have been the main driver of the effect on visceral adipose tissue,” says Prof. Knut Mai, head of the Department of Human Nutrition at DIfE. Interestingly, this effect was independent of the slight weight loss seen in both groups, highlighting the importance of the specific nutrient composition.

These findings contribute to a deeper understanding of the role of specific nutrients and dietary patterns in reducing visceral adipose tissue and improving the cardiometabolic profile.

Optimizing dietary recommendations for 50 plus
“The results are particularly relevant for older people who have an increased risk of cardiometabolic diseases,” explains Nina Meyer, first author of the study. “The specific diet might serve as a preventive measure against such diseases without the need for drastic weight loss and without the fear of losing muscle mass.” The findings of the study might be used to improve dietary recommendations for people aged 50 and over and to adapt individual nutritional counseling. “Compared to other diets, the NutriAct dietary pattern can be more easily integrated into everyday life and help to reduce the risk of cardiovascular disease in the general population,” says Meyer. In future studies, the researchers want to further clarify the underlying mechanisms of these effects and analyze the influence of dietary patterns on other cardiovascular systems, such as heart function, in more detail.

Original publication:
Meyer, N. M. T., Pohrt, A., Wernicke, C., Pletsch-Borba, L., Apostolopoulou, K., Haberbosch, L., Machann, J., Pfeiffer, A. F. H., Spranger, J., Mai, K.: Improvement in Visceral Adipose Tissue and LDL Cholesterol by High PUFA Intake: 1-Year Results of the NutriAct Trial. Nutrients 16(7):1057 (2024). [Open Access] 

Background information:

“NutriAct” competence cluster for nutrition research
The joint project “Nutritional Intervention for Healthy Aging: Food Patterns, Behavior, and Products” – NutriAct for short – was one of four nutrition research competence clusters funded by the Federal Ministry of Education and Research with 12 million euros. The central aim of the joint project, which was launched in 2015, was to improve the health status of people aged fifty to seventy years. To this end, the research association in Berlin/Brandenburg combined nutrition research and business. The Scientific Director of the DIfE, Prof. Tilman Grune, headed the association, in which over 30 research institutions and companies were involved. The NutriAct funding period ended on March 31, 2022, but the results will continue to be evaluated and published.

The NutriAct nutrition study was a major sub-project and aimed at using the specific NutriAct dietary pattern to prevent age-related lifestyle diseases, improve cardiovascular function, cognition and metabolism, prevent fatty liver disease and maintain muscle mass. The 319 women and 183 men between the ages of 50 and 80 who took part in the study adhered to the prescribed nutritional intervention for three years.

Composition of the diet [daily intake in % of total energy] in the NutriAct nutrition study NutriAct dietary pattern

NutriAct dietary pattern
Fat: 35-40 %
> Saturated fatty acids: ≤ 10 %
> Monounsaturated fatty acids: 15-20 % Polyunsaturated
> Fatty acids: 10-15 %
Protein: 15-25 %
Carbohydrates: 35-45 %
Dietary fiber: ≥ 30 g

Control diet
Fat: 30 %
> Saturated fatty acids: ≤ 10 %
> Monounsaturated fatty acids: ≥ 10 % Polyunsaturated
> Fatty acids: 7-10 %
Protein: 15 %
Carbohydrates: 55 %
Fiber: ≥ 30 g

Measuring your waist circumference correctly
You can measure your waist circumference yourself using a measuring tape, ideally before breakfast. Stand facing the mirror with your feet approx. 15 cm apart. The upper body should be free. The measuring point is located in the middle between the bottommost costal arch and the upper edge of the pelvic bone. Breathe out during the measurement (without drawing in your stomach).

The waist circumference should

> not exceed 88 cm in women and
> not exceed 102 cm in men.

Higher values indicate abdominal obesity and the risk of complications such as heart disease, strokes and type 2 diabetes is significantly increased. People who have a larger waist circumference and a BMI over 25 kg/m2 should consult their GP for a further risk check.

Scientific Contact:
Prof. Dr. med. Knut Mai
Head of the Department of Human Nutrition at DIfE and Comm. Clinic Director at the Medical Clinic for Endocrinology and Metabolic Medicine at the Charité – Universitätsmedizin Berlin
E-Mail: knut.mai(at)dife.de / knut.mai(at)charite.de

Nina Meyer
Medical Clinic for Endocrinology and Metabolic Medicine at the Charité ─ Universitätsmedizin Berlin
E-Mail: nina.meyer(at)charite.de

Press Contact:
Press and public relations
Phone: 033200 88-2335
E-Mail: presse(at)dife.de