Raw bitter almonds contain toxins that can be lethal, 7-10 raw bitter almonds contain a toxic level of hydrocyanic acid, which is why the raw form of bitter almonds is strictly prohibited in certain countries including the USA. Once a bitter almond is treated/roasted hydrocyanic acid is neutralized or removed making them safe to use for culinary purposes.
Sweet almonds are far more common, since non-sweet almonds are only produced in trees with recessive genes producing the bitter flavor. Bitter almonds can have more than 40 times the hydrocyanic acids than sweet almonds which is why they are both roasted or baked to protect against cyanide toxicity. They both appear similar having brown skin and white interiors, but bitter almonds are slightly smaller with more of a point. The astringent bitter flavor is the most distinguishing characteristic difference, obvious in a single nut taste. Bitter almonds have a shorter shelf life due to the high unsaturated fat content, so they must be stored in airtight containers kept out of direct sunlight, moisture, and heat; they can also be frozen in sealed containers.
Bitter almonds and extracts in medicinal terms are used for treatment of inflammation, spasms, localized pain, and respiratory distress. It can be used both topically and internally consumed. In the past it was used for a range of health conditions in raw form, but is no longer recommended due to toxicity risk.
One cup of bitter almonds contains 529 calories, 45 grams of fat including 11 grams of polyunsaturated fat, 18% of daily recommendations of potassium, 44% of dietary fiber, 40% of protein, 24% of calcium, 61% of magnesium, 18% iron, 5% vitamin B6, only 1 mg of sodium, and 3.6 grams of sugar.
Bitter almonds are used in production of certain cosmetics, soaps, lotions, and conditioners. Bitter almonds are preferred for its fragrance and high concentration of active ingredients that help decrease inflammation and beautify skin.
Bitter almond essential oil has vermifuge, germicidal, febrifuge, antibacterial, sedative, antifungal, anti-intoxicating, anesthetic, aperient, antiviral, anti-carcinogenic, antispasmodic, and anti-inflammatory properties mainly due to glycoside amygdalin, hydrogen cyanide, and benzaldehyde components.
Bitter almond trees contain one of the highest sources of B17 which is known to help prevent and treat cancer. Banning from the USA in 1995 of raw form due to toxic concerns caused much debate, with claims of it having little anticancer effect and claims of it to the contrary. Cyanide is naturally present in bitter almonds, but it is also in apples, lima beans, peaches, apricots, bamboo shoots, flaxseed, barley, and sorghum in pits and seeds which typically are discarded. Recent research shows the toxicity of bitter almonds is good for inhibiting growth of cancerous cells in certain cancers.