Peanuts are technically legumes, not true nuts. They can cause allergic reactions in some people, which can range from mild itching to severe anaphylaxis. If you have a known peanut allergy or a history of severe allergic reactions, you should avoid peanuts.
Brazil nuts are incredibly high in selenium, a mineral that is essential for good health but can be toxic in large amounts. Consuming too many Brazil nuts could lead to selenium toxicity.
Macadamia nuts are high in calories and fat, which can contribute to weight gain if consumed in excessive amounts. They are also very rich, so overeating them can lead to digestive discomfort.
Cashews are a common allergen, and some people may experience allergic reactions. Also, they contain a natural toxin called urushiol, which is also found in poison ivy. Proper roasting or processing usually removes this toxin, but if improperly processed, it can cause skin irritation or other allergic reactions.
Like peanuts, chestnuts are not true nuts, but rather a type of seed. They are safe to eat once cooked, but can be toxic if consumed raw.
Pine nut syndrome, also known as pine mouth, is a temporary taste disorder that can occur after eating certain types of pine nuts. It can cause a metallic or bitter taste in the mouth that lasts for several days or even weeks.
Consuming hickory nuts in large quantities can potentially lead to digestive discomfort due to their high fiber content.
It's important to note that horse chestnuts are not edible. They look similar to edible chestnuts but contain a toxic compound called aesculin, which can cause serious health issues if ingested.