A high-protein diet can help to keep you feeling fuller for longer, helping to fight obesity. A new study uncovers the mechanisms involved and offers hope of a safer, more easy alternative.
More than a third of adults in the United States are classed as obese. And with obesity comes an increased risk of a range of potentially life-threatening conditions. Therefore, finding ways to reverse this epidemic is paramount.
High-protein diets are known to keep you feeling fuller for longer. In some people, this can lead to reduced overall calorie intake and weight loss.
However, diets focused on a heavy protein load can be difficult to maintain and often carry their own health risks. Some of these risks include constipation due to a lack of dietary fiber, increased heart disease risk (with higher red meat consumption), and reduced kidney function for people already at risk of kidney problems.
Because of the dangers and difficulties of a high-protein diet, researchers are keen to understand how they work with the hope of replicating their effects.
Mariana Norton, one of the researchers from the current study, explains, “Diets high in protein are known to encourage weight loss but adhering to them can be difficult. Identifying the mechanisms that sense the protein may allow us to use drugs or functional foods to hijack appetite regulation and treat obesity.”
In effect, the aim is to keep the beneficial effects of protein without the protein.
To this end, Prof. Kevin Murphy and his colleagues — from Imperial College London in the United Kingdom — focused on phenylalanine. They chose this compound because previous studies had shown that it can reduce appetite. It appears to manage this feat by triggering the release of appetite-related hormones in the gut.
During digestion, proteins are broken down into amino acids, and one of these is phenylalanine. It is classed as an essential amino acid because our bodies cannot manufacture it, and therefore need to consume it.
In the gut, phenylalanine is detected by calcium-sensing receptors. Activation of these receptors stimulates the release of glucagon-like peptide-1 (GLP-1) in the brainstem. GLP-1 helps to improve glucose tolerance, among other tasks.
Although researchers believe that phenylalanine helps to influence appetite through GLP-1, the exact mechanisms have not been uncovered. There seems to be more involved than just one hormone pathway. The current study takes a fresh look.
The study paper is titled “Rectal and oral administration of L-phenylalanine suppresses food intake and modulates neuronal activation in appetite-regulating brain regions in rodents,” and the findings will be presented by Norton at the 2017 Society for Endocrinology annual conference, held in Harrogate, U.K.
Mice were administered phenylalanine either orally or rectally. The two different routes allowed the team to assess its effects on different parts of the gut. Over the following 24 hours, the mice’s food consumption was measured, and the parts of the brain involved in appetite were monitored.
Phenylalanine, given both orally and rectally, reduced the rodents’ appetite and increased activity in the parts of the brain known to be involved in regulating appetite. Even when a quantity of phenylalanine 10 times less than the daily levels expected from a high-protein diet were administered rectally, these effects were still measurable.
“Understanding how food is detected in the gut may help to identify ways of treating or preventing obesity. The next step is to establish whether phenylalanine can drive similar appetite-reducing effects in humans.”
It seems that phenylalanine works to suppress appetite using a number of pathways in the gut. Of course, the study does not prove that phenylalanine has the same effect in humans, so more work will need to be done. However, the findings are intriguing and raise further questions to be answered.
For instance, as previously mentioned, the release of GLP-1 with phenylalanine was expected, but the researchers also measured a reduction in levels of gastric inhibitory peptide, which is a hormone that induces insulin secretion. This was a surprising result and warrants further investigation.
Can forskolin help me lose weight?
With almost two-thirds of adults in the United States being overweight or obese, it is no surprise that the use of weight loss supplements, such as forskolin, is commonplace.
Forskolin, in particular, shot to popularity after praise from Dr. Oz on his television show.
However, the scientific evidence may not support the hype that surrounds this prominent weight loss supplement.
Fast facts on forskolin:
- Forskolin is a supplement made popular for its possible use in weight loss.
- Forskolin comes from a plant called Coleus forskohlii.
- In theory, forskolin aids weight loss by helping create enzymes called lipase and adenylate cyclase.
Forskolin is a plant supplement derived from the root of a member of the mint family known as the Indian coleus that grows in Thailand, Nepal, and parts of India.
While forskolin has long been used in folk medicine for asthma treatment and various other ailments, it is marketed nowadays, as a weight loss supplement.
The coleus plant
The tropical coleus plant has long been used in Ayurvedic medicine, a subtype of medicine with origins on the Indian subcontinent and long incorporated into western wellness practices.
Traditionally, forskolin and the coleus plant were used to promote general health and wellness. Forskolin was also used for asthma and breathing disorders.
In its natural habitat, local people boiled the root of the coleus to make tea to drink and to promote wellness. Today, it is most popular as a weight loss supplement.
Theoretically, forskolin aids in weight loss by helping create enzymes called lipase and adenylate cyclase.
These two enzymes free fatty acids from the body’s cells. When the fatty acids are free, they can be burned as fuel. When the body burns fatty acids, it may reduce fat without affecting lean muscle mass.
Unfortunately, this theory does not consider that for weight loss to happen a calorie deficit must also occur. In other words, a person must burn more calories than they take in through food and drink. If this fails to happen, a person will not lose weight.
So, while forskolin may raise fat burning capabilities, this is irrelevant without a nutritious diet and exercise to support the calorie deficit.
Studies on the efficacy of forskolin
Study results on forskolin and weight loss are mixed.
While a study conducted on a small group of overweight and obese men showed that forskolin reduced their body fat, it had little effect on their weight. It also increased their testosterone. Higher levels of testosterone are linked with lower weight and sustained weight loss.
Other studies conducted had varying results. In a double blind study, 23 overweight females were given 250 milligrams (mg) of forskolin twice a day for 12 weeks. The studies show that forskolin failed to help the women lose weight. However, the supplement did seem to lessen any additional weight gain while they were taking it.
Therefore, it is too much to say that forskolin is the solution to weight loss. While studies suggest it may slow weight gain or raise testosterone levels in men, forskolin is not a miracle weight loss solution that some supplement distributors and television medical personalities claim.
Forskolin may have skyrocketed into the public eye after praise for its potential to help people lose weight, but it has other possible uses that scientists are currently studying. These potential uses include the following:
- treating asthma
- treating cancers
- improving heart strength in congestive heart failure
- treating glaucoma
- lowering blood pressure
- stimulating a suntan
There have been some scientific studies done on forskolin’s effect on cancer in animals that suggest it may have a positive effect. No human studies have been done on that subject, however, so these studies are, at best, inconclusive.
If you wish to try forskolin, it is available for purchase online. However, it is important to speak to a doctor before trying this or any other supplement.
Most people who are familiar with weight loss supplements are familiar with warnings about the numerous side effects. However, unlike many supplements that have been available on the market, forskolin itself seems mostly safe.
Many weight loss supplements interact with the cardiac system by raising blood pressure and stimulating cardiac tissue. Because of the way forskolin is metabolized by the body, most scientists believe that it does not interact with the cardiac system the way of other weight loss supplements.
However, just because there are no known interactions with forskolin itself, it does not mean that forskolin supplements are safe.
Weight loss supplement manufacturers can often hide other potentially dangerous ingredients in their supplements. Because of these tactics, the U.S. Food and Drug Administration (FDA) caution consumers against many weight loss supplements on the market.
Additionally, in Europe, there have been reports of acute poisoning following consumption of products containing forskolin, possibly due to contamination.
Consequently, it is important to be cautious with any supplement or herb, as they are not monitored by the FDA and could have issues with purity, quality, or dosage.
Aside from the risk of contamination, forskolin can pose risks for certain groups and should not be taken by the following:
- people with kidney disease
- those with low blood pressure
- people taking medication for blood pressure or slower heart rate
- people taking blood thinners
Forskolin is not a weight loss miracle drug, and there is no substitute for proper diet and exercise.
If, after following a healthful, low calorie diet and exercise program, a person is not losing weight, they may want to consult their doctor. The medical professional can recommend ways to help with weight loss, but forskolin is probably not going to be one of them.
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