Although excess body fat might contribute to the development of certain diseases, it is important to not simply think of fat as bad or unhealthy. You have different types of fat, or adipose tissue, in your body, each one serving a distinct—and important—function. One is designed to store energy for when your body requires additional food, such as when you fast, and the other is ready to burn energy to make heat when you are cold. Adipocytes, or fat cells, also play a key role in the regulation of appetite, glucose, and energy balance through secreting adipokines, or messengers, such as leptin and adiponectin.
Some adipose tissue is also protective against obesity and metabolic diseases, so it is thought of as the healthier fat. New research is demonstrating that there might be a way to switch the type of fat you have to this healthier type, so it works for your health, not against it, through a process known as ”beiging.”
Types of Adipose Tissue
For decades, it was presumed that there were two main categories of adipose tissue: white adipose tissue and brown adipose tissue. In very general terms, brown adipose tissue is healthier, as this is the one involved in thermogenesis, or the burning of calories to make heat. It is protective against obesity and contains a higher number of mitochondria. White adipose tissue stores excess calories and generally exists in the stomach area and subcutaneously. It is the one associated with disease, including diabetes and cardiovascular disease.
However, recent research has discovered a third type of adipose tissue: beige. As its name implies, it is a blending of the two types of adipose tissues, although it has a distinct gene expression. Beige adipose tissue has the low basal expression of white fat cells but still will respond to the cyclic AMP stimulation as needed. This feature suggests that the cells have the capacity to switch between storage and creating energy depending on the needs of the body.
Beige adipose tissue arises when brown-like cells accumulate in white adipose tissue, which happens more often in subcutaneous adipose tissue than visceral fat tissue. The addition of the brown cells increases the capacity to burn calories through thermogenesis. There are certain components of these cells that provide them with the special characteristics, including PR domain containing 16 (PRDM16), which is like a switch that differentiates brown adipose tissue. The cells also express the genes for uncoupling protein 1 (UCP1), which typically are reserved for brown adipocytes and are associated with mitochondrial cells, which is where energy production occurs. In general terms, the more mitochondria in a cell, the more energy it can burn.
There are ways to boost the beiging to combat obesity and obesity-related diseases. As an added bonus, many of the recommendations have multiple health-boosting benefits beyond converting your adipose tissue.
Exercise provides many health benefits, including reducing stress, facilitating weight loss, and increasing strength. One way it might provide its benefits, especially in terms of weight loss, is through instigating beiging. In a study on mice, exercise on wheels for just 11 days led to a significant increase in the UCP1 expression. This suggests that physical activity increases the number of mitochondria and the expression of the marker for UCP1, which is typically associated with brown adipocytes. As more mitochondria enter the white tissue, more beige cells arise.
Another reason exercise promotes the development of beige adipose tissue is due to an increase of irisin. Irisin is a hormone that increases fat loss, glucose tolerance, and energy expenditure. Irisin levels are directly related to muscle mass. In a study using murine cells, differentiated cells were incubated with irisin alongside a control group that was not. Irisin led to upregulations of the markers for brown adipose tissue in the white adipose tissue, including UCP-1 and PCG-1A. The researchers also performed the study on live mice and found similar results. These studies suggest that exercise fights obesity not just by reducing the number and size of fat cells but also through switching at least some of the white adipose tissue to the healthier beige variety.
Another way to stimulate the production of beige adipose tissue is through your environment, including your social activities. One study on rats found that enriched living conditions simulated the upregulation of PRDM16 and UCP1 levels, suggesting beiging. This study defined enriched living as social interactions, increased physical activity, and new experiences. Although physical activity played a role in the environment, it was not the sole reason for the beiging effect.
The researchers looked at several groups, including those with an enriched living situation that did not have as extensive of an exercise regimen. That group still lost weight, although those who did have access to an exercise wheel had a more effective browning. This suggests that social interactions, learning new information, and trying new hobbies could also help boost the beiging effect, even if your lifestyle changes do not include physical activity.
Capsaicin has a reputation for assisting in weight loss, and this might be due to its ability to facilitate thermogenesis and beiging. In terms of the beiging properties of food ingredients, capsaicin is one of the best studied, and the one that has advanced into human studies. Capsaicin is the component of hot red peppers that give them their spicy properties. A closely related particle is capsinoids, which are found in the less-spicy red peppers. Both have demonstrated the capacity to enhance fat oxidation and increase energy expenditure to aid in weight loss. One way they do this is through brown adipose tissue. In one study, the group with positive markers of brown adipose tissue had a 3-fold increase in their energy expenditure compared with those who did not after consuming capsaicin. Another study found that consuming 9 mg per day of capsinoids in a capsule form for a period of six weeks led to increased activity in brown adipose tissue, even in the group with low activity levels, when exposed to cold temperatures. Similar thermogenic effects in connection with capsaicin have been demonstrated in beige adipose tissue as well. One study demonstrated that capsaicin inhibited adipogenesis and increased the expression of browning-specific genes in white adipose tissue, especially at higher doses.
Omega-3 Fatty Acids
You have probably heard time and time again to get your omega-3 fatty acids to gain from their anti-inflammatory and other health-promoting properties. Another reason to do this is to boost the conversion of your white adipose tissue into beige or brown. Specifically, you want to consume eicosapentaenoic acid (EPA), a type of omega-3 fatty acid. One study found that after treating fully differentiated human white adipose subcutaneous tissue cells of women who were overweight with 100 – 200 uM of EPA for 24 hours, there were alterations in the mRNA expressions of the genes suggestive of beiging. There was an increase in the number of mitochondria and the gene expressions for fatty acid oxidation, which burns fat as energy. There was also an induction of specific genes of beige, including PRDM16 and UCP1, as well as expression of specific markers for beige cells.
Vitamin A is a fat-soluble vitamin whose metabolites, such as retinoic acid and other retinoids, play a key role in differentiation of tissues and cells around the body. The body stores excess vitamin A and its metabolites in the liver and adipose tissue, and it might do more than simply sit in the adipose tissue. A certain metabolite, all-trans-retinoic acid (ATRA), has been shown to stimulate beiging. In one study, cells treated with ATRA had an increased number of mitochondria and UCP1 expression. The study also looked at the effects of ATRA on mice.
A group of mice consumed feed with 5 IU of vitamin A per kilocalorie and six of the mice received subcutaneous amounts of ATRA at levels of 50 mg/kg of body weight per day (this would be equivalent to .375 grams in a 165-pound person, which is quite high). Despite not reaching statistical significance, there was a definite increase in mitochondrial gene expression in the treated mice’s white adipose tissue. This study looked at a specific metabolite of vitamin A, rather than vitamin A. However, it does suggest that beiging could be another possible benefit of consuming sufficient vitamin A in your diet, although more research needs to be done to confirm the exact dose.
Alpha-Lipoic Acid (ALA)
Alpha-lipoic acid is an important antioxidant naturally produced by the body, which supports mitochondrial health. It demonstrates anti-obesity properties, and this might be due to its beiging effect on the body. A study looked at the effects of subcutaneous adipocytes treated with ALA at doses of 100 and 250 uM over a period of 24 hours. After treatment, the cells had increased mitochondria numbers and markers of brown adipocytes.
As with many of the above, consuming resveratrol increased the markers of brown adipocytes, including UCP1 and PRDM16, in white adipose tissue. In a study on female mice consuming a high-fat diet, researchers gave one group 0.1 percent resveratrol in their feed and the control group did not have any resveratrol. The researchers also performed a similar experiment on cultured cells. Their findings pointed to the beiging of the white adipose tissues based on the increased markers.
Curcumin has numerous health benefits, thanks to its anti-inflammatory and other health-promoting properties. Additionally, it has the power to induce the beiging of adipose tissue. In one study, curcumin was found to increase the number of mitochondria in the white adipose tissue. It also increased the ability of the cells to perform beta-oxidation and augment lipolysis. Additionally, there was increased expression of UCP1 and other specific makers of brown adipose tissue. This finding suggests it converts the white adipose tissue into the more fat-burning and healthier beige or brown adipose tissue. Curcumin’s fat-fighting benefits do not stop simply at converting white brown tissue to beige or brown; it also has the potential to inhibit the genesis of adipose tissue as another way to help combat obesity.
The herb berberine has many health benefits, including helping prevent and treat diabetes. One reason for its efficacy in weight regulation and diabetes prevention might stem from its effects on beiging white adipocytes. A study on db/db mice, which are a variety that has impaired glucose tolerance and marked obesity, treated one group of mice with berberine. This group lost weight despite no significant difference in caloric intake. The berberine reduced the size of the white adipose cells, and it activated AMPK, which increases the energy production of adipocytes. There was also an increased number of mitochondria, suggesting beiging.
There are other ways to stimulate the production of brown or beige fat cells, including cold temperatures, conjugated linoleic acid, and green tea. Many of the studies on beiging thus far are still in the in vitro and animal trial phase. However, there are promising results demonstrating that there are ways in which you might be able to increase the number of brown and beige fat cells in your body, especially in your subcutaneous white adipose tissue.