Other products and farming practices A concern is the case of medications, which are routinely tested on animals to ensure they are effective and safe, and may also contain animal ingredients, such as lactose, gelatine, or stearates. There may be no alternatives to prescribed medication or these alternatives may be unsuitable, less effective, or have more adverse side effects. Experimentation with laboratory animals is also used for evaluating the safety of vaccines, food additives, cosmetics, household products, workplace chemicals, and many other substances. Vegans may avoid certain vaccines, such as the flu vaccine, which is commonly produced in chicken eggs. An effective alternative, Flublok, is widely available in the United States. Farming of fruits and vegetables may include fertilizing the soil with animal manure even on organic farms, possibly causing a concern to vegans for ethical or environmental reasons. "Vegan" (or "animal-free") farming uses plant compost only. Research and guidance A 2022 review indicated that a vegan diet may be effective for reducing body weight, lowering the risk of cancer, and providing a lower risk of all-cause mortality. People on a vegan diet with diabetes or cardiovascular diseases may have lower levels of disease biomarkers. A 2022 meta-analysis found moderate evidence that adhering to a vegan diet for at least 12 weeks may be effective in individuals with overweight or type 2 diabetes to induce a meaningful decrease in body weight and improve glycemia. A 2021 Cochrane review of randomized controlled trials found that there is "currently insufficient information to draw conclusions about the effects of vegan dietary interventions on cardiovascular disease risk factors". A 2018 meta-analysis of observational studies concluded that "In most countries, a vegan diet is associated with a more favourable cardio-metabolic profile compared to an omnivorous diet". A 2022 meta-analysis of prospective cohort studies concluded that vegan diets are associated with reduced risk of Ischemic Heart Disease, but no clear association was found for cardiovascular disease and stroke. A 2020 review of inflammation biomarkers found that a vegan diet was associated with lower levels of C-reactive protein compared to omnivores. There is inconsistent evidence for vegan diets providing an effect on metabolic syndrome. There is tentative evidence of an association between vegan diets and a reduced risk of cancer. A vegan diet without caloric restriction may reduce high blood pressure similarly to diets recommended by medical societies and portion-controlled diets. Vegans may be at risk of