When fat is ingested, the body produces an enzyme called lipase that is responsible for breaking down the fat into a form that is readily absorbed by the body. When Xenical is swallowed it will inhibit the activity of the enzyme lipase resulting in approximately 30% less fat absorption. Less fat absorption results in less caloric absorption, and thus weight loss.
Does it Work?
There have been several large double blind studies that have been completed to test the efficacy of this medication. Two of these studies tested 120 mg of Xenical taken three times daily with a low calorie diet for one year followed by a second year of treatment while on a weight maintenance diet (JAMA, 281:235, 1999; Lancet, 352:167, 1998). The group given the medication lost approximately 19.8 – 22 pounds during the course of the study compared to an average of 13.2 pounds in the placebo group a difference of 6.6 – 8.8 pounds. In the second year of the study the placebo group regained between 8.8 – 13.2 pounds while the treatment group gained back 3.3 – 6.6 pounds. In a third study, patients were put on a low calorie diet which resulted in a weight loss of 22 pounds. Half the group was then given Xenical while the other group was given placebo. After one year the Xenical group had gained back 5.7 pounds while the placebo group regained 9.7 pounds. In addition, 24% of the group taking Xenical did not regain any weight while 16% of the placebo group remained weight stable. A fourth study tested the effect of Xenical in diabetic patients. The group given Xenical lost approximately 4 pounds more than the placebo group (Am J Clin Nutr, 69: 1108, 1999). The conclusion of the sum of these trials is that Xenical does in fact promote weight loss. This data does not tell us how much of the weight loss comes from muscle and how much comes from fat. It can be assumed that weight loss from fat restriction will result in loss from fat and muscle to a certain degree. These data can not guarantee sustained weight loss past two years because the subjects in the studies were only followed for this period.
Neglecting the Side Effects
The most recent study out of Quebec City confirmed the above stated results. Dr. Michael Lean (could the last name be a coincidence?) stated, “This drug works effectively for around three-quarters of the people who take it… because the drug is not absorbed, side effects are negligible, provided patients stay on a low fat diet.” This is an interesting statement because we have never met a patient on Xenical who said that the side effects are negligible and we are willing to bet that Dr. Lean has not spent too much time taking Xenical himself. These side effects include flatulence with discharge, oily spotting and fecal urgency in 20 – 40% of the patients. These side effects are significantly less if the patient stays on a low fat diet. This begs the question, why are we giving a fat blocker to someone who needs to be on a low fat diet anyway? Is the weight loss due to the efficacy of the medication or is it the intentional or subconscious fat restriction due to fear of “negligible” side effects?
Aside from the uncomfortable side effects listed above there are many more significant side effects that happen “behind the scenes.” To begin with, fat absorption is non-selective. There are two main fats that are found in the diet… omega-3 and omega-6 (this is an oversimplified for the point of this brief discussion). The omega-6 fats are the fats that are primarily responsible for fat gain, blood clotting and inflammation. These fats are found in abundance in vegetable oils, farm grown animal fats and certain nuts such as peanuts and cashews. The omega-3 fats are responsible for increasing metabolism, decreasing inflammation, protecting the blood vessels and inhibiting clotting. These fats are found in wild harvested, cold Atlantic fish, certain seeds such as flax seed, certain nuts such as walnuts and range grown animal foods. Xenical does not distinguish between the two fats and thus will inhibit both. This would normally not be a problem if, as a result of the Standard American Diet (SAD), we were not so deficient in omega-3 fats. However, a patient taking Xenical may run the risk of serious health effects as a result of a deficiency of these healthy fats.
A study recently published in the reputable journal, Archives of Internal Medicine, reviewed the current literature on omega-3 fats and came to some astonishing conclusions. The main conclusion was that the omega-3 fats from dietary sources could prevent cardiac death and nonfatal heart attack (Arch Intern Med 2001; 161: 2185-92). An earlier review of the literature found that people who were at high risk of heart disease could decrease their risk of heart disease related death by 40 – 60% simply by eating 1.3 – 2 oz of fish weekly (Eur J Clin Nutr 1999; 53: 585-90). The average Xenical patient may need to double or triple this amount in order to maintain healthy levels of this fat, and that is assuming that the person has chosen the proper kind of fish and prepared it properly.
There are other worries regarding Xenical’s potential harmful effects to the heart, and overall health. It is well known that Xenical will prevent your body from absorbing fat soluble vitamins such as A, D, E and K. Vitamin E plays an important role in the prevention of heart disease and immune function, vitamin K is important in the maintenance of healthy clotting and vitamin D is important in the prevention of calcification of the arteries (Circulation. 1997; 96: 1755-1760) and proper maintenance of strong bones.
Although these vitamins can be replaced through supplementation, another class of vital nutrient is not so simple to replace. These nutrients make up a class called carotenes that are found in colorful fruits and vegetables such as carrots, tomatoes, radishes, etc. The carotenes include beta carotene, alpha carotene, gamma carotene, lutein, lycopene, zeaxanthine, and many others. Scientists believe that they have only touched the surface of the list of carotenes to be found in foods. Because there are literally hundreds of carotenes in nature, we cannot readily supplement appropriately. Studies have determined that higher carotene intake results in a protective effect against heart disease (J Nutr 1999;129:5–8 [review]) and cancer. Research has also determined that Xenical may decrease circulating carotenes by as much as 50%. This would surely have a negative effect on the cardiovascular system and immune system. The maker of Xenical suggests that Xenical has been shown to improve blood pressure, cholesterol and blood sugar, thus resulting in protection from heart disease. They conveniently fail to mention the miniscule amounts by which these parameters change such as a 2 point decrease in blood pressure, 5 point decrease in total cholesterol and a change in hemoglobin A1C (long term blood glucose control) of one-fifth of one percent (0.18%). They also fail to take into account the effect of decreased omega-3 fats, fat-soluble vitamins and carotenes.
Data pooled from seven controlled studies showed that 9 out of 747 patients on Xenical developed breast cancer compared to only 1 out of 579 on placebo. These results could not be confirmed in the two published two-year studies (Medical Letter 41: 1055 June 18, 1999: 56). Although we cannot definitively link Xenical use to breast cancer at this time, the possibility is there and needs to be considered when choosing this therapy. Alpha linolenic acid, one of the omega-3 fatty acids, and the carotenes may help prevent breast cancer. Xenical’s inhibitory effect on the absorption of this fat may predispose the patient to breast cancer.
The last issue worth mentioning is that when a person takes “a pill” to lose weight, many other healthy habits have a tendency to disappear, with the underlying thought that “I’m taking a pill, so I don’t have to exercise, etc.” Ever see a person order a Diet Coke with their piece of cake for dessert?
The Cost of Weight loss
Xenical is very expensive, with a monthly cost of $118. This translates into approximately $3000 per two-year course of treatment at which time you can expect to lose a maximum of 15 pounds. Thus the cost of one pound of weight loss is approximately $200 (this does not factor in the cost of new undergarments or the use of Depends for the up to 40% of people with the “negligible” side effects). Compared to other, more traditional forms of weight loss, including proper exercise, this is very expensive. Some people will make the argument that their insurance pays for it, but keep in mind that one way or another we end up paying for those drugs, usually through increased insurance premiums.
I Have Read… but I Still Want to Take Xenical
Thank you for educating yourself before choosing your path. As an educated consumer you can now work to decrease the potential for side effects. Below we have listed some suggestions for foods and products that may help you maintain at least a minimal level of health while on this medication.
Eat foods that are high in carotenes. These include any of the following: carrots, sweet potatoes, squash, corn, tomatoes, watermelon, spinach, colorful peppers, lemons, oranges, prunes, greens, mangoes, tangerines. Any fruit or vegetable that is colorful is likely to have larger amounts of carotenes. A dietary supplement containing mixed carotenoids should be added as well. One such product is Caroteam by Vitamin Research Products.
When you eat foods with fat try to eat cold Atlantic fish or range grown meats such as range grown cattle and/or chickens. Range grown refers to animals that are permitted to graze in fields eating live food instead of processed animal feeds. This will help assure the presence of healthy fats. Those who cannot work these foods into their lifestyle should take an essential fatty acid supplement such as potent fish oil capsules.
You should get at least 800 I.U. of vitamin E, 25,000 IU of mixed carotenes and 1,000-2,000 mg of vitamin D daily. Although these suggestions exceed the RDA, keep in mind that the RDA was not designed to apply to people on Xenical.
Please realize that following the above suggestions will most definitely result in weight loss, regardless of taking Xenical or not. In our opinion it makes sense to try the less expensive way first.
**Xenical is a registered trademark of Roche