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Body and mind

Menopause does not affect the body’s ability to metabolize fat

Researchers have wondered whether menopause affects women’s ability to metabolize fat, but a new study refutes this.

The older we get, the harder it is to get rid of the fat around the waist, but for women, menopause has nothing to do with it.

This is the conclusion of a new study recently published in the Journal of Clinical Endocrinology and Metabolism.

The researchers investigated the ability of women to metabolize fat, and it drastically declines with age. But this decline is not greater during menopause than at other times in their life.

“We examined women before, during and after menopause, and the loss of ability to metabolize body fat is not greater for menopausal women than for women in other age groups,” explains Peter Arner, Senior Researcher, Lipid Laboratory, Department of Medicine, Karolinska Institutet, Huddinge, Sweden.

Examined 82 women to determine their ability to metabolize fat

The study is the first of its kind to investigate changes over time in how women metabolize fat, converting it to energy.

As women reach menopause, the composition of their sex hormones changes dramatically, and the sex hormones influence the body’s ability to convert fat into energy. The obvious conclusion was therefore to think that this change in sex hormone composition might affect fat metabolism as a whole.

Researchers from Karolinska Institutet investigated, over 7–16 years, the fat metabolism of 82 women aged 24–62 years in 2004.

The researchers did this by taking biopsies of the women’s fat tissue and examining their ability to mobilize fat cells through lipolysis, which is the process of converting the triglycerides in fat cells into energy.

The researchers used the same method 7–16 years later (average 13).

“This is a widely recognized method that has been used for 30 years to determine fat metabolism,” explains Peter Arner.

No difference between older and young women

During the study period, 42 of the women went into menopause, and 11 had already reached menopause when the trial began.

The results showed that women’s ability to metabolize fat did not depend on whether they were menopausal.

For all the women, fat metabolism declined by about one third during the average of 13 years, regardless of whether they aged from 24 to 37 years old or from 50 to 63 years old. Although younger women metabolized fat better than did older women, the relative decline was similar for all age groups.

“Women’s ability to metabolize fat declines as they grow older. This is a fact, but it has nothing to do with menopause,” says Peter Arner.

Genetic factors may cause fat metabolism to decline

Changes in sex hormones related to menopause do not cause the ability to metabolize fat to decline, but what does make it decline?

Peter Arner speculates that the decline may result from changes in hormones other than sex hormones. Only the composition of sex hormones changes drastically in menopause, whereas the levels of other hormones are not affected.

The decline in ability to metabolize fat may also result from genetic changes, since ageing naturally affects the DNA of cells.

The genes that maintain the ability to metabolize fat may not function as well with ageing as they did in adolescence.

“There are several possibilities, and we are investigating them,” says Peter Arner.

Both men and women should exercise more

Peter Arner’s research group performed similar experiments with men and showed that their ability to metabolize fat declines with age.

The result for both sexes is that more effort is required to eliminate fat around the waist, and many people have noticed this.

However, Peter Arner has good advice on how both sexes can increase fat metabolism, even as the years tick by.

“Both sexes can increase fat metabolism by exercising. This is a great way to counteract the effects of ageing,” says Peter Arner.

Influence of ageing and menstrual status on subcutaneous fat cell lipolysis” has been published in the Journal of Clinical Endocrinology and Metabolism. In 2015, the Novo Nordisk Foundation awarded a grant to Peter Arner for the project Mechanism and Clinical Impact of Human Adipose Tissue Turnover.

Peter Arner
Senior researcher
The group focuses on the regulation of the turnover of human fat cells and their lipid content, in particular how inflammatory factors within adipose tissue regulate the size and number of the fat cells. We have detected a network of microRNAs and transcription factors which controls inflammation in adipose tissue. The mechanisms conducting this network are dissected at the cellular and molecular levels. By investigating patients following successful bone marrow transplantation we also study bone marrow as an important source of the generation of new human fat cells.