The side effects of using Alli don't affect everybody. The closer you stay to the official eating plan suggested by Alli, the less chances you will experience side effects. This is because Alli is meant to block a percentage of the fat you consume, for a total of up to 25 percent, according to MyAlli.com. That fat will pass through your body undigested. If you choose to eat foods low in fat, the percentage that passes through will be small and the side effects are likely to be mild. However, if you eat meals that contain more than 15g of fat, the side effects will be more severe.
Gastrointestinal Problems
The most common side effects of Alli have to do with the digestive system. According to eMedTV, more than 20 percent of people taking Alli will experience abdominal pain and over 17 percent will suffer fecal urgency, gas and oily spotting or stools. The symptoms are more severe following high-fat meals. Diarrhea and fatty or gas with a stool discharge are also possible. While not as common, it's also possible to suffer from fecal incontinence when taking Alli, which means you won't be able to stop spontaneous bowel movements.
Nutrient Malabsorption
Taking Alli can reduce the absorption of certain nutrients, including fat-soluble vitamins like vitamins A, D and E, according to Vanderbilt University. Alli seems to also inhibit the absorption of omega- 3 and omega-6 fatty acids from food sources. Since these nutrients are essential for the health of skin, bones and eyes, malabsorption can lead to health problems over the long run.
Other Symptoms
According to eMedTV, Alli can cause back pain and an increased risk of contracting a sinus infection. Alli can also cause serious side effects that require medical attention, sometimes immediately. For example, people who suffer from gallbladder disease can see a worsening of their symptoms. Alli can also cause allergic reactions that result in hives, difficulty breathing and rashes. The most serious possible effect of Alli is liver damage. This can be identified by loss of appetite, yellow eyes or skin and dark urine.
Member Comments