Brown Fat and Health

When the body’s brown fat is activated, you can lose more than 9 pounds of bad white fat each year, without changing your diet or exercise regimen.

Scientists have only recently found out that adults do have brown fat. Before their discovery, scientists thought brown fat in adult bodies are there mainly to help keep babies warm. Scientists also thought that brown fat goes away as the body becomes more muscular.

Three new studies published in the New England Journal Of Medicine show that more than half of adult men and women have sufficient brown fat that, if activated, could burn significant amounts of white fat.

Kirsi A. Virtanen, MD, PhD, of the University of Turku, Finland, and colleagues examined the brown fat in 5 young men. One of these men had 2.2 ounces of brown fat. The researchers say, "If the brown [fat] in this example were fully activated, it would burn an amount of energy equivalent to approximately 4.1 kilograms [9 pounds]" of white fat in one year.

What are brown fats?

Brown fats were first detected by scientists when they take PET scans. Brown fats are actually a problem for scientists during scans because they shine brightly when activated, making it difficult for doctors to spot what they are looking for.

To solve this problem, technicians came up with several ways of preventing brown fat activation, including giving patients beta-blocker drugs.

Researchers examined brown fats and found that they appear closer to muscle than white fat. Newer researches indicate that it might be possible to induce the body into producing more brown fats.

How do brown fats work?

Brown fats are stimulated when you are cold. Virtanen and colleagues used this knowledge in their research. They instructed their 5 participants to spend 2 hours – under-dressed – in a cold room, with one foot soaking periodically in a bucket of ice water. The volunteers then underwent PET scans. The researchers found that activated brown fats burned white fat as fuel. This process gives off heat (and thus, burns a lot of fat).

More recent studies about brown fats, such as those by Wouter D. van Marken Lichtenbelt, PhD, and colleagues at the University of Maastricht, Netherlands; and by Aaron M. Cypess, MD, PhD, of Beth Israel Deaconess Medical Center, Boston, and colleagues, revealed that:

  • Obese people have less brown fats than lean people.
  • Women have more brown fats than men.
  • Older people have less brown fat than young(er) people.
  • People with blood sugar have less brown fat than people with normal blood sugar.

These findings show that there is a "direct correlation between the activation of brown adipose tissue and metabolic measures that indicate the presence or absence of good health," says NIH researcher Francesco S. Celi, MD in an editorial accompanying the studies.

Cypress and colleagues say that it’s possible that half of all men and women have at least 1/3 of on ounce of brown fat in their bodies – in the neck, where brown fats is spotted most easily.

If brown fat is fully activated, the researchers think that 1.75 ounces of brown fat would account for 1/5 of a one person’s "total resting energy expenditure" – most, if not all, from burning white fat and not sugar.

Practical application

With their unique ability to burn white fats, researchers conclude that "finding ways to promote brown fat activation will have a major impact on the obesity epidemic."

To boost this theory, it was discovered that one of the body’s "messenger proteins" – BMP7 – promotes growth of brown fat and might become the center of new obesity treatments.

Source: WebMD