Saturday, October 31, 2015
Bitter Orange for Weight Loss
Until the mid-1990's, the most popular herbal weight loss formulas were based on ephedra, the Asian herb that is the natural source of ephedrine. Contrary to common belief, ephedra itself was not outlawed in the US, just the synthetic chemical, ephedrine. Most herb product manufacturers, however, chose to stay on the safe side of the law and stopped carrying products that contained either the synthetic chemical or the herb.
Some weight loss product formulators turned to bitter orange extract as a source of synephrine (also known as para-hydroxy-synephrine or p-synephrine) as a replacement for ephedrine. Synephrine has a chemical structure that is somewhat similar to ephedrine and some of the same effects on weight loss metabolism as ephedrine. It increases calorie burning, particularly the burning of fat. However, people who don't understand how the product works have given it a bad name.
Bitter Orange is Safe
Traditional Chinese Medicine has used bitter orange peel for nearly 2,000 years, usually to treat gastrointestinal complaints. Since the time of European settlement, South American curanderos and curanderas have used bitter orange primarily to treat anxiety and insomnia.
Although the chemical structures of the bitter orange chemical synephrine and ephedrine are similar, their functions in the body are very different. Ephedrine binds to receptors that activate the production of the stress hormones epinephrine and norepinephrine in adrenal glands. The bitter orange chemical synephrine does not. Ephedrine causes an increase in heart rate and blood pressure (by binding to beta-1 and beta-2 adrenoreceptors). Synephrine does not raise pulse rate or either systolic or diastolic blood pressure (because it binds to beta-3 adrenoreceptors). Ephedrine is derived from the chemical phenylpropanolamine and easily crosses the blood-brain barrier. Synephrine is derived from the chemical phenylethanolamine and does not easily cross the blood-brain barrier.
Ephedrine is soluble in fats, and binds to belly fat. Synephrine is not soluble in fat, and does not bind to belly fat. Ephedrine stimulates appetite, and synephrine reduces it. Ephedrine worsens insulin resistance. Synephrine improves it. Cardiovascular complications have been reported after the use of ephedrine. No cardiovascular complications were reported by any of the 480 participants in clinical trials, according to Dr. Sydney J. Stohs, former dean of the school of pharmacy at Creighton University.
Many articles on the Internet refer to the presence of a stimulant chemical called octopamine in bitter orange extracts and bitter orange peel. More than twenty published analytical studies have failed to find more than 1% as much octopamine as synephrine in the bitter orange samples tested, and most of the published studies found no octopamine at all. The standardized testing materials prepared by the National Institute of Standards and Technology do not contain octopamine in their product.
Bitter orange is in fact regulated by the US Food and Drug Administration, under the Dietary Supplements Health and Safety Act of 1994.
Bitter Orange Is Proven to Work
There have been 12 double-blind and placebo-controlled studies involving 450 volunteers (90 of whom received a placebo). Taken together, these studies show the efficacy of bitter orange extract for losing weight. Weight loss volunteers received bitter orange extracts that were standardized to provide from 10 to 80 mg of p-synephrine every day, along with up to 704 mg of caffeine.
Not all the clinical trials of bitter orange extracts were conducted to test weight loss. Some were conducted to establish its safety. In the nine clinical trials that studied weight loss, bitter orange increased metabolic rate. It accelerated weight loss after it was taken for at least 6 weeks. And 80% of bitter orange extract users in one of the studies reported that exercise was easier when they took the herb.
The longer the herb is taken, the greater the rate of weight loss. Six-week studies usually found about a 3-pound weight loss. Eight-week studies usually found about 6 pounds of weight loss. The one 10-week study found a 10-pound weight loss, on average, for test participants taking synephrine with caffeine (in the same product). In a study conducted by Seifert and collaborators, taking synephrine standardized from bitter orange peel increased calorie burning 8% a day without increasing heart rate or blood pressure.
The effects of p-synephrine are greater in women than in men. However, men get a greater thermic effect, that is, more calorie burning, when the product is taken on an empty stomach. There were no adverse effects of the bitter orange extracts tested in any of the 12 clinical trials.
The Benefits of Bitter Orange Aren't Limited to Weight Control
Bitter orange does not just contain p-synephrine. It also contains some natural antioxidants known as flavonoids, including naringenine. In a clinical trials conducted by Dr. Stohs and collaborators, a combination of flavonoids with p-synephrine (which occurs in the fruit naturally) nearly triples calorie-burning, up to about 200 calories a day. That may not sound like a lot but it's about half a pound a week during the first six weeks the product is used, and even more later.
But that's not all. Researchers at the Robarts Research Group in London, Ontario have found that naringenin stops the process of insulin resistance in the skeletal muscles. It reduces the production of large, fluffy pieces of very low-density lipoprotein cholesterol, and helps muscles take glucose out of the bloodstream more efficiently. This lowers blood sugar levels and indirectly lowers triglycerides and blood pressure--at least in test animals. The benefits of bitter orange flavonoids, even without the much-discussed p-synephrine, probably go a long way toward correcting the high blood pressure, high blood sugar, high cholesterol, high triglycerides, and belly fat weight gain so common in middle age.
Bitter orange isn't a miracle herb. It's merely a very useful herb. Dieters still have to do the hard work of calorie restriction for their diets ultimately to work--but taking bitter orange extracts makes their task easier.
Photo credit: Bitter oranges (C. aurantium) in the Jardines del Alcázar de Sevilla, Spain. Jared Preston via Wikimedia Commons.