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Changes in fat composition during menopause may affect dementia risk, according to new research. Ekaterina Demidova/Getty Images
  • Menopause results in changes in a woman’s hormones, which have many effects on the body, including fat distribution.
  • While different types of fat distribution have different effects on a person’s overall health, the composition and type of fat a person has also has an impact.
  • A new study has suggested that the composition of fat that a woman has in mid-life, around the time of menopause, can affect the likelihood they will experience cognitive difficulties later in life.

The key to tackling obesity may be energy balance, but it is more complicated than “calories in calories out.”

In fact, the type of fat the body stores its energy in has an effect on our overall fat balance and metabolism, which in turn affects other aspects of our health, such as cardiovascular and brain health for example.

A recent study carried out by researchers at various sites across the United States investigated fat deposits at different sites in the heart and aorta in a cohort of 531 women with a mean age of 51. This age was expected to overlap with menopause.

White fat is denser than brown fat. But how brown and white fat distribution affects health postmenopause has previously proved difficult to study as imaging is difficult.

Scientists took images using electron beam CT scanning of the heart and aorta and carried out tests to determine fat density at three different sites: inside the sac surrounding the heart, fat located outside that sac, and on the fat that surrounds the aorta, the body’s largest artery leading away from the heart.

Researchers also carried out cognitive tests on the women involved, a median of 13.4 years after scans were taken when women were an average of 61 years old.

They discovered that the greater the amount of brown fat discovered around the aorta during midlife and menopause in the women, the higher the cognition of these women later in life.

Conversely, the higher the levels of white fat discovered around the aorta in these women, the lower their cognition was at the follow-up over a decade later.

The paper is published in the journal Alzheimer’s and Dementia.

Not all fat cells are the same.

Some brown fat cells are packed with mitochondria, the energy-making part of a cell, and iron stores (which make them brown) and are burned to create heat for the body, a process known as thermogenesis.

White fat cells are used to store energy, and beige fat cells have some of the properties of both and are generally used for storage but can also play a role in thermogenesis, similar to brown fat cells. Burning or storing fat cells has an impact on overall adiposity and weight.

Research into the differentiation of these cells is important for understanding obesity.

Hormones play a role in the regulation of fat cells.

Estradiol, one of the main types of estrogen found in the human body, plays a role in the regulation of thermogenesis by brown fat cells and, therefore weight loss.

This hormone, along with other types of estrogen, decreases during menopause. A drop in this hormone following menopause or removal of the ovaries is associated with an increased desire for food and weight gain.

At the same time, hormone replacement therapy is shown to help reverse the development of obesity and metabolic dysfunctions in postmenopausal women. This is important as cardiovascular disease risk is shown to increase in women after menopause.

However, estrogen could also protect against inflammation in women, due to the actions of subcutaneous fat, according to a recent study conducted in mice.

Prof. Franck Mauvais-Jarvis, professor of medicine in endocrinology and metabolism at Tulane University and director of Tulane Center of Excellence in Sex-Based Biology & Medicine, who was not involved in the research, told Medical News Today:

“Premenopausal women have a predominant subcutaneous adipose tissue distribution (pear body shaped) and the menopausal transition redistributes adipose tissue toward a central, abdominal distribution (apple body shape). Menopause also increases cardiovascular fat.”

“Abdominal adipose tissue distribution is associated with more systemic inflammation and insulin resistance and increased cardiovascular risk.”

— Prof. Franck Mauvais-Jarvis, professor of medicine in endocrinology and metabolism

Researchers say the finding is an association and does not show causation but have hypothesized that higher levels of brown fat are associated with better metabolic health and lower markers for inflammation.

The researchers write that amyloid beta plaques found in people with Alzheimer’s disease first start to deposit in mid-life, and the fact that the fat that surrounds the aorta is closer to the brain than other cardiac tissue tested, means it may have more of an effect on inflammation markers in the brain than cardiac fat in other areas.

“Menopause itself and the associated estrogen deficiency is associated with cognitive decline and abdominal, visceral fat has been associated with poor cognitive performance.”
— Prof. Mauvais-Jarvis

“The findings of the paper are interesting and suggest that the quality and quantity perivascular adipose tissue surrounding the thoracic aorta can play a bi-directional role in cognition/memory loss and [Alzheimer’s disease] in women. The radiodense one [white fat] may be inflamed and release inflammatory factors in the vessels that predispose to [Alzheimer’s],” said Prof. Mauvais-Jarvis but added that “Mechanistic studies are needed to address this causality.”

The findings emphasize the need for menopausal and postmenopausal women to consider the cardiovascular risk associated with additional abdominal fat and be supported by healthcare professionals to minimize risk.

Dr. Nisarg Patel, Gynecologist & Obstetrician at Nisha IVF Centre in Ahmedabad, India explained to Medical News Today the changes menopause causes in body fat distribution.

“Menopause brings about changes in fat type and distribution, specifically an increase in visceral fat. This shift can have significant implications for cardiovascular risk, as visceral fat is metabolically active and associated with an increased risk of heart disease,” he said.

“Understanding the influence of hormonal changes and adopting healthy lifestyle choices are vital in managing cardiovascular risk during menopause,” he added.