nut is a hard-shelled fruit of some plants having an indehiscent seed.
While a wide variety of dried seeds and fruits are called nuts in English,
only a certain number of them are considered by biologists to be true nuts.
Nuts are an important source of nutrients for humans.
Nuts are a composite of the seed and the fruit, where the fruit does not
open to release the seed. Most seeds come from fruits, and the seeds are
free of the fruit, unlike nuts such as hazelnuts, hickories, chestnuts and
acorns, which have a stony fruit wall and originate from a compound ovary.
Culinary usage of the term is less restrictive, and some nuts as defined in
food preparation, like pistachios and Brazil nuts, are not nuts in a
biological sense. Everyday common usage of the term often refers to any
hard-walled, edible kernel as a nut.
Some fruits and seeds that do not meet the botanical definition but are
nuts in the culinary sense:
• Almonds, pecans and walnuts are the edible seeds of drupe fruits —
the leathery "flesh" is removed at harvest.
• Brazil nut is the seed from a capsule.
• Candlenut (used for oil) is a seed.
• Cashew nut is a seed.
• Gevuina nut
• Horse-chestnut is an inedible capsule.
• Macadamia nut is a creamy white kernel
• Malabar chestnut
• Corn nut is a cooked kernel
• Peanut is a legume.
• Pine nut is the seed of several species of pine (coniferous trees).
• Pistachio nut is the seed of a thin-shelled drupe.
People who consume nuts regularly are less likely to suffer from coronary
heart disease (CHD). Almonds and walnuts can lower serum LDL cholesterol
concentrations. Although nuts contain various substances thought to possess
In addition to possessing cardio-protective effects, nuts generally have a
very low glycemic index (GI). Consequently, dietitians frequently recommend
nuts be included in diets prescribed for patients with insulin resistance
problems such as diabetes mellitus type 2.
Nuts contain the essential fatty acids linoleic and linolenic acids, and
the fats in nuts for the most part are unsaturated fats, including
Many nuts are good sources of vitamins E and B2 (riboflavin, an
antioxidant), and are rich in protein, folate, fiber, and essential
minerals such as magnesium, phosphorus, potassium, copper, and selenium.
Raw or unroasted walnuts are considered the healthiest, with twice as many
anti-oxidants as other nuts.
Nuts are most healthy in their raw form. The reason is that up to 15% of
the healthy oils that naturally occur in nuts are lost during the roasting
process. Roasting at high temperatures could also cause chemicals that
advance the aging process to form.