That vitamins are essential for the health it is well known. Yet, as revealed by data from the Study and Research Center on Obesity of the University of Milan, 75% of the villagers take too little, because they do not regularly follow a healthy and balanced diet.
But how many do we really need? In which alimony They are? What functions do they have in the body? And again, for what reason according to the most up-to-date studies the C represents the drug of the future? We try to to clarify examining, one by one, the most important ones.
Vitamin A (or retinol)
It is fat-soluble, that is, it dissolves and becomes assimilable in fats: "Its absorption therefore depends on the quantity and quality of the lipids we introduce with food, as well as on the secretion of bile acids by the liver", explains Dr. Giulia Sturabotti, expert in nutrition, hygiene and preventive medicine in Rome.
What is Vitamin A used for? «In the organism it carries out multiple functions: it is an antioxidant, it intervenes in protein synthesis, it stimulates immune response and it is essential for the health of bones, teeth and eyes: it is part of the components of rhodopsin, which is a photosensitive protein present on the receptors of retina, which gives the eye sensitivity to light ».
Vitamin A it is found in foods in two forms: «As retinol it is present in those of animal origin, in particular in liver of chicken and turkey, in fish oil, eggs and moles dairy product; on the other hand, in yellow-orange vegetables, such as carrots, pumpkin, peppers, peaches and melons, and in green leafy vegetables, for example spinach and broccoli, there are carotenoids (including beta-carotene), precursors of vitamin A.
Some are also a source of egg yolk and milk. Since vitamin A is sensitive to heat, it is good to consume foods that contain it raw, when possible, or subject them to quick and non-aggressive cooking ", explains the expert.
There are eight, all water-soluble (they dissolve in water): B1 or thiamine; B2 or riboflavin; B3 or PP or niacin; B5 or pantothenic acid; B6 or pyridoxine; B8 or H, also known as biotin; B9 or folic acid; and B12 or cyanocobalamin.
"This summer, the publication, in the scientific journal Journal of Clinical Oncology, of an authoritative research conducted by the Ohio State University, according to which those who take too many vitamins B6 and B12 has an almost doubled risk of having lung cancer, especially if you are a male and a smoker.
But, apart from the fact that it is not clear how much the probability of getting sick depends on cigarettes and how much from these substances, it should be noted that the research refers to massive doses of supplements taken for many years and certainly not of vitamin B produced with a balanced diet, which respects the indications of the recommended intake levels (Larn) », explains Dr. Sturabotti.
Because we cannot do without the B vitamins, found in particular in whole grains, in animal foods, in legumes, in nuts and some green leafy vegetables such as spinach? «Speakers in energy metabolism and in the transmission of nerve impulses and are essential for the health of skin, nails and hair.
La B12, then, present exclusively in foods of animal origin, it contributes to the production of red blood cells and to the synthesis of DNA. One of its deficiencies is responsible formegaloblastic anemia », Adds the expert.
Aside from the B2, the B6 and, to a lesser extent, the B12, are all sensitive to heat, therefore it is advisable to limit cooking times as much as possible: «In the case of eggs, for example, the ideal would be to consume them raw or soft-boiled, as long as they are very fresh and their origin is known».
Vitamin C (or ascorbic acid)
It is water-soluble, i are very rich in it vegetable, serves the body to synthesize important substances, such as the neurotransmitter noradrenaline (an antistress), steroid hormones, bile acids and collagen: "Furthermore, promotes intestinal absorption of iron», Dr. Sturabotti points out.
But it is above all on his own antioxidant and even antitumor activity, as well as stimulating the immune system, which for some time has focused the attention of doctors and researchers:
"A major test conducted in mice by the Perlmutter Cancer Center in New York and recently published in Cancer Cell revealed that high doses of vitamin C, administered by injections and in combination with traditional therapies, are a formidable weapon against neoplasms, especially those of the blood, and can represent one of the most effective strategies against cancer.
Injected into animals, the Vitamin C in fact, it has been shown to block the proliferation of cancer stem cells, taking away their energy. There is still a long way to go to include it in therapeutic protocols, but these are important confirmations of its effectiveness.
Among other things, it was also found to be able to regenerate vitamin E in the body, which in turn is a powerful antioxidant ». All the more reason to make sure every day adequate portions of seasonal fruit and vegetables, to be consumed as raw as possible: Among the main sources there are citrus fruits, kiwis, black currants, strawberries, green leafy vegetables large, such as lettuce, radicchio and spinach, tomatoes and yellow and red peppers ».
Vitamin E (tocopherol)
It is fat-soluble and has excellent antioxidant properties: "Protects tissues from free radical damage. In particular, it is capable of counteracting cognitive decline and the onset of neurodegenerative diseases such as l’Alzheimer.
Not enough: it stimulates the immune system, intervenes in the transmission of signals between cells, fights inflammation on an allergic basis, especially those affecting the skin and, in addition, it regulates cholesterol and platelet aggregation, thus protecting the cardiovascular system », says Dr. Sturabotti.
It is found mainly in the vegetable oils (olive, sunflower, peanut, soy and corn) and wheat germ, but it is also found in dried fruit (for example in walnuts, almonds and hazelnuts) and green leafy vegetables.
"Its absorption is favored by fats: therefore, if the source of vitamin E is vegetables, it is important to dress them with olive oil, or combine them with ingredients rich in lipids, such as avocado" . This vitamin is particularly unstable to heat and it is good to take it into account when preparing food, using the oils preferably raw.
«Fat-soluble and thermostable, it ensures the correct synthesis of some proteins, including osteocalcin, which form and maintain strong bones because they favor the fixation of calcium. So it is indispensable for the health of the skeleton. In addition, involved in the mechanisms of blood coagulation, in particular it allows the activation of prothrombin and other coagulation factors ", explains the expert.
Vitamin K is mainly present in foods of plant origin: «You can take it in adequate quantities using aromatic herbs such as sage, thyme and basil, the vegetables green leaf and i legumes, for example beans. Lower quantities are found in meat, especially in chicken, in cereals and in dairy products», Concludes our expert.
More folic acid if you want a baby
"During the pregnancy it is important for the expectant mother to ensure an adequate supply of vitamin B9 (folic acid): this substance is essential for the correct development of the neural tube, the structure that will give rise to central nervous system of the fetus (brain and spinal cord) and which begins to form soon after conception.
«Vitamin B9, which deteriorates easily under the effect of light and heat, is contained in foods such as i whole grains, broccoli, spinach, bananas and legumes», Explains Dr. Cinzia Longobucco, a nutrition biologist in Bari.
The recommended daily dose is 0,5-0,8 mg and on sale you also find enriched foods, such as milk and yogurt. Also, if you plan to have a son, be aware that gynecologists do not recommend resorting to supplements even before conception to be sure not to suffer from deficiencies.
The D isn't just for bones
Vitamin D is considered a pro-ormone, because in the body it regulates the synthesis of some important substances including insulin. It is therefore not only essential for bone health: "Protects the heart, reducing the risk of developing atherosclerosis and hypertension, prevents the diabetes and helps to counteract the loss of lean mass typical of old age », explains Dr. Carmen Madio, a nutrition biologist in Milan.
How is it synthesized? «Regular exposure to sunlight is the most effective way to avoid deficiencies. This substance is in fact present only in some foods, especially of animal origin, such as fish, dairy products, eggs and meat».
Little time outdoors and a predominantly vegetarian diet may explain why nearly 60% of adults in the country have a vitamin D deficiency. To learn more about its benefits, click here.
They really need enriched foods
The addition of vitamins to food products is governed by a European Union regulation. "According to current legislation, the added nutrients must be present in the final product in significant quantities, such as to benefit the consumer, and not exceeding precise levels of security, so as not to put health at risk », explains Dr. Sturabotti.
But are these foods really useful? "At the moment there is no scientific evidence showing, for example, the usefulness of drinking fruit juice enriched with vitamin C: it is much better to focus on freshly squeezed fruit juice.
The added foods do not improve the health of those who follow a healthy, varied and balanced diet. If anything they can be useful in particular situations, such as pregnancy, old age or when following diets, such as vegan, which expose you to the risk of deficiencies. Be careful especially not to be misled: the chips fried in envelopes, even if enriched with vitamins, remain junk food».
The signs that can lead to suspicion of a deficiency
In the Western world today, severe vitamin deficiencies are a distant memory. “Instead, there are many people who present slight deficiencies, usually due to an unbalanced diet, low in precious substances, or to incorrect lifestyle habits, such as smoking and alcohol consumption, which reduce the body's absorption capacity.
Symptoms are usually few, non-specific (tiredness, ease of infection) and difficult to diagnose. However, there are some vitamins that should be monitored with a simple blood test.
For the prevention ofosteoporosis, starting from menopause all women should ask for the vitamin D dosage. If you suffer from small bleeding in the gums, your vitamin C levels should be evaluated.
The dosage of the Vitamin B12 (important for the proper functioning of the neurological system), especially in elderly people and vegetarians: an insufficient level could favor the cognitive decline»» Explains Dr. Giulia Sturabotti.
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