The listed internal organs belong to the group of the so called sub-products or offal.
The liver, which is a concentrate of hematopoietic microelements and all vitamins (especially vitamin A, B2, B12, PP, choline), has the most important role in medical nutrition.
It contains up to 18% protein, 3% fat, a lot of cholesterol (200-300mg per 100g against 60-70mg in 100g meat). A popular objection against eating liver is the belief that this is the organ that stores the toxins in the body.
It is true that one of the roles of this organ is to neutralize toxins (like drugs, chemical agents), but it does not store these substances. The toxins, which cannot be eliminated by the organism, are more likely to accumulate in the fat tissue of the body and the nervous system. It’s just the opposite – the nutrients present in the liver provide the organism with the tools it needs to get rid of the toxins. The main disadvantage of eating liver is the amount of cholesterol it contains.
A small slice of beef liver contains 90% of the daily ration of cholesterol for an adult, and its excessive consumption may increase the risk of cardiovascular events. The other sub-products also have large nutritional values: tongue, heart, kidneys.
The tongue is simple to boil, it has some connective tissue, up to 16% protein and only 3% fat, as well as high iron content.
The heart is approximately equal in calories and protein to the white chicken meat. 100g portion of beef heart has only 95 calories and 15g protein, which is 27% of the recommended daily intake of protein in men and 32% in women. 100g kidneys contain nine times more than the daily requirement of B12 – a vitamin that is essential for the production of new red blood cells
The same amount gives us more than twice of the daily recommendation for riboflavin and about 20% of the daily needs of niacin. The vitamins from the B group work together to accelerate the metabolic reactions in the body. 100g cooked kidneys also give almost 18% of the requirements for folate.
Folic acid is vital for the build-up of new cells in the whole body, which is especially important for women during pregnancy.
On the question how often to eat sub-products, I would answer that it is a matter of personal judgment and health status, but we could vary our diet with some of these products once every two weeks. It should be mentioned that all of these sub-products contain purines and accordingly are contraindicated in gout and uraturia.
The diseases of the stomach, accompanied by high acidity also impose their limited consumption due to their strong juice releasing action.