Science has identified over thirty vitamins, each designated by a letter of the Latin alphabet. The most well-studied are vitamins A, B, C, D, E, and K.
Vitamin A was first discovered in butter and egg yolks. Later, a substance found in carrots was shown to convert into vitamin A in the human body. Rich sources of vitamin A include green onions, cabbage, red peppers, parsley, spinach, red tomatoes, potatoes, horseradish, beet greens, unripe walnuts, rowan berries, black currants, rose hips, apricots, oranges, and lemons.
A deficiency of vitamin A in the diet can lead to infections, colds, and acute contagious diseases. Children who do not consume enough vitamin A in their diet may experience stunted growth and poor development. It is essential to include vitamin A-rich foods in the diets of children and nursing mothers, such as carrots, cabbage, fish oil, and liver.
Vitamin B refers to a group of vitamins. They are most abundant in rye bread, legumes, yeast, and meat. A lack of vitamin B can lead to severe nervous system disorders. Fish oil, whole milk, mushrooms (especially porcini), and yeast are excellent sources of vitamin D.
If a child does not get enough vitamin D, they may develop rickets, causing soft bones, an enlarged abdomen and head, and crooked legs, which can lead to a child growing up with bow legs or a hunchback. Vitamin E, found in bread, salad, and other foods, is crucial for human development.
Vitamin K has the ability to stop bleeding and heal wounds. It is abundant in tomatoes, cabbage, spinach, and edible nettles.
Knowing the importance of vitamins and the foods that contain them is not enough; one must also learn how to preserve them in food. For instance, the primary sources of vitamin C are vegetables, fruits, greens, and berries, particularly seasonal products. If we examine the same vegetables in the fall and spring, we will find that they contain twice as much vitamin C in the fall compared to the spring. Potatoes can lose 75-80% of their vitamin C in the spring, while apples can lose up to 90%. If part of the cabbage is kept at room temperature and another part in a cellar at 4-5 °C (39-41 °F), after a month, the first will lose 25% of its vitamin C, while the second will lose only 10%. Vegetables lose even fewer vitamins when stored in refrigeration at temperatures of 0-2 °C (32-36 °F). The ideal storage temperature for potatoes and fruits is 2-3 °C (36-37 °F), for fresh cabbage it’s 1-2 °C (34-36 °F), and for sauerkraut, it’s 3-4 °C (37-39 °F).
The primary cause of the destruction of vitamins A and C is the oxidation of food by oxygen. Oxidation increases with heating and boiling. Cooking food in a tightly sealed container filled to the brim results in less vitamin loss due to reduced air and oxygen exposure. Therefore, it is advisable to cook food quickly, avoid overcooking, and consume it immediately. Cooked food that sits for 3-4 hours can lose up to 40% of its vitamins, so it is not recommended to prepare dishes for several days in advance.
Vitamins C and B dissolve in water and leach into the broth during cooking. Vitamins A, B, E, and K dissolve in fats, so it is essential to sauté root vegetables and onions in fat, stirring well to ensure each piece is coated with a fatty film; this film helps protect the vitamins from the damaging effects of oxygen.
In food cooked in a copper pot with a damaged coating, vitamins can disappear. When boiling peas or beans, it is common to add a bit of baking soda to speed up the cooking process, but this should be avoided as baking soda destroys vitamins.
The outer layer of vegetables contains more vitamins, so it is important to peel them thinly. Potatoes cooked in their skins lose 25% of their vitamins, while peeled potatoes lose 80%. Cabbage should be cooked for 20-30 minutes, potatoes for 40 minutes, and sautéed onions should be added 10 minutes before the dish is fully cooked. Potatoes placed in boiling water lose 7% of their vitamin C, while those placed in cold water before boiling lose 35%. To preserve vitamins in jelly, the juice extracted from berries should be poured into hot cooked starch. For vinaigrettes, vegetables should be boiled in their skins under a lid and then quickly cooled.
To retain the vitamins in dried fruits and vegetables, they should be treated with a substance containing sulfur before drying; this kills bacteria without affecting the vitamins. Canning factories now produce canned goods without air exposure, which helps preserve vitamins. In fermented vegetables, lactic acid forms, which also helps retain vitamins. A barrel of pickles should be tightly sealed to prevent air exposure.
In spring, when vegetables and fruits have fewer vitamins, it is advisable to add products made by vitamin factories to dishes, such as jams and marmalades. Vitamin-enriched products in the form of powders, tablets, and extracts should be stored in a dry, cool place, and vitamin A, in particular, should be kept in the dark, as it degrades when exposed to light.
The science of vitamins is relatively new, but it has already uncovered the causes of many diseases known as vitamin deficiencies (conditions caused by a lack of vitamins in the diet). If a person consumes food lacking sufficient vitamins, they may develop diseases such as scurvy, night blindness, rickets, beriberi, and others. It is essential to remember the significant role vitamins play in human life and to follow conditions during food preparation that ensure vitamins are fully preserved in the diet.