Studies have not established the effect of almonds on breast cancer
By "almond," we mean the nut of the sweet almond tree (Prunus amygdalus dulcis), not the bitter almond nut (Prunus amygdalus amara). Almonds are an excellent dietary source of vitamin E, magnesium, copper, chromium, manganese, phosphorus, riboflavin and melatonin, as well as soluble fiber and monounsaturated fats. Almonds contain numerous phytochemicals, including quercetin, quercitrin, isorhamnetin, naringenin, catechin, epicatechin, and morin. Almond components have been shown to have high antioxidant and anti-inflammatory properties. Consumption of almonds has been shown in numerous studies to help lower cholesterol, reduce blood sugar, and reduce the risk of cardiovascular disease. Habitual almond consumption does not in and of itself appear to lead to weight gain.
Cancer-related effects of eating almonds
Almond consumption has been associated with lower risk of colon cancer. Although almonds share some of the favorable characteristics of other tree nuts such as walnuts, there is little specific evidence concerning almond consumption and breast cancer risk.
Almonds are an excellent source of melatonin. Melatonin protects against breast cancer in several ways, including by reducing aromatase activity within the breast, thereby reducing estrogen production.
Additional comments
Ideally, almonds should be eaten unroasted and with their skins on. Almond milk can be a good substitute for milk and almond butter is a very good substitute for peanut butter. Almond oil (i.e., sweet almond oil) has been found to have beneficial effects on cholesterol profile and it appears that the favorable effect of almonds is due to components in the oil portion of these nuts. Pure almond extract normally is manufactured using a small amount of bitter almond oil but it is relatively safe in small quantities, especially when used in baking and other forms of cooking involving heat.
Marzipan can be a relatively healthy confection, as long as it is made with ground sweet almonds. Marzipan made with a substantial portion of bitter almonds or peanuts, and persipan made with apricot or peach kernels should be avoided.
Almond oil can safely be used in the massage of seriously ill patients and patients undergoing chemotherapy. On the other hand, bitter almond oil, which can cause cyanide poisoning, should not be ingested or used on the skin.
People with a history of oxalate kidney stones should limit or avoid almonds, since consumption of almonds has been shown to increase urinary oxalate excretion.
Laetrile, a synthetic form of amygdalin (found in bitter almonds and apricot kernels), has long been used as an alternative cancer treatment, although it is less popular now than in the 1970s and early 1980s when numerous laetrile clinics in Tijuana, Mexico were established to meet the demand from U.S. cancer patients. The claim that laetrile is an effective and benign cancer treatment is not supported by sound clinical data. Laetrile has been found ineffective in shrinking tumors, increasing survival time, and alleviating cancer symptoms. Although sometimes referred to as vitamin B17, laetrile is not a vitamin. Some cases of acute accidental cyanide poisoning have been reported with the use of laetrile in combination with vitamin C. Vitamin C is known to increase the conversion of amygdalin to cyanide and reduce body stores of cysteine, which is used to detoxify cyanide.
Note that while we are continually searching for new evidence concerning this food, there is not much interest in it among cancer researchers so few recent studies are available.