For vitamin D is a group of fat-soluble and steroid molecules, real hormone precursors (proormonali). Which regulates bone metabolism and modulates the intestinal absorption of calcium, iron, magnesium, phosphates, and zinc; for humans, the most important related molecules are vitamin D3, also known as cholecalciferol, and vitamin D2, called ergocalciferol. Here we will give you a complete guide about what Foods Have Vitamin D?
Vitamin D can be of exogenous origin, i.e., introduced with food, or endogenous, i.e., synthesized in the skin; however, in the strict sense of the term, none of these is biologically active. The activation process requires an enzymatic conversion, i.e., hydroxylation (addition of the -OH group), which occurs in the liver and kidneys. The endogenous synthesis, caused by the action of ultraviolet rays (UV) type B. It is regulated by a negative feedback mechanism that prevents a possible toxic effect; however, we must not forget that excessive sun exposure can increase cancer risk to the skin.
Since, under favorable conditions, the synthesis of vitamin D occurs regularly. Today there is a tendency to consider cholecalciferol as a nutrient no longer. But as a hormone.
As anticipated, vitamin D plays a critical role in homeostasis and calcium metabolism. It has an indisputable protective action. In the prevention of rickets and osteomalacia, and it is known that failure to reach peak bone mass. In developing age – for which cholecalciferol is necessary – constitutes a risk factor for osteoporosis; however, other hypothetical health effects remain unclear. Studies carried out on the role of a possible vitamin D. Supplement about the incidence of general mortality do not reveal any exciting correlation; at the moment, no particular recommendations have been disclosed regarding vitamin D intake for preventive purposes.
General information on vitamin D
The sum of the metabolisms of the various molecules of vitamin D. Especially vit D2 and vit D3 – determines the serum level of 25-hydroxycalciferol or calcidiol (25-OH-D). Therefore, following the transformation that occurs in the kidneys, calcitriol is the active form of vitamin D. The latter circulates in the blood like a hormone and regulates. The concentration of calcium and phosphate by promoting normal bone growth and skeletal remodelling. Calcitriol also acts on the nerve and immune functions.
However, it is undeniable that the serum levels of calcidiol are significantly influenced. By the food composition, especially if the exposure to UV- B rays is not sufficient. Diet and vitamin D supplements play a crucial role, especially. In the Nordic countries, where the sun does not fully rise at certain times of the year. But it is equally true that to do this it would be necessary to produce significant quantities. At these latitudes, a process not fully exploited even in the light seasons.
Now let’s see which foods contain higher levels of this prohormone and what are needs to be met.
The dietary content of vitamin D
Only a few foods, all of the animal origin, contain significant amounts of vitamin D; other products that can contribute, albeit secondarily, to reaching the daily quota are mushrooms – but not vegetables.
Indicatively, 80% of the vitamin D requirement is guaranteed by solar radiation even if the research institutions have established. The daily request on the hypothesis of a total absence of exposure to UV-B rays. L ‘ cod liver oil is rich (210 mg / 100 g). Even if you prefer to date different products. Then the traditional as pearlfish oil, capsules of oil krill, oil algae, etc.
Among fish, fatty ones – such as salmon – and especially. Those belonging to the category of bluefish include bonito, mackerel, lizard, tuna belly, herring, etc. Can contain up to 25 µg / 100 g. As for meat, on the other hand. Only the liver – a product belonging to the offal or fifth quarter – contains, a level higher than the “trace” level (0.5 µg / 100 g).
Speaking of dairy products, only butter – up to 0.75 µg / 100 g – and particularly fatty cheeses – up to 0.5 µg / 100 g – (Holland et al., 1991) show small levels of vitamin D. While eggs – in particular, the yolk – contain about 1.75 µg / 100 g.
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No specific surveys have been carried out on the levels of vitamin D intake in the Italian diet. The vitamin D content of foods is generally expressed by weight (µg / 100 g of edible portion). But the former “International Unit” (IU) is still in use (1UI = 0.025 µg of vitamin D).
An old estimate of vitamin D intake levels in the Italian population (Saba, 1990), with reference. To the average consumption of fatty cheeses (9 g / day), eggs (24 g / day), offal (6 g / day), and fish (19 g / day), allows us to assume that the average intake is around 2 µg / day.
This hypothesis is supported by the data obtained by analyzing. The American population in which, despite the widespread use of foods fortified in vitamin D. Shows average levels of intake equal to 1.25 – 1.75 µg / day (USDA, 1983). Note: in the United States, milk is fortified with 10 µg – corresponding to 400 IU – of vitamin D per quarter litre.
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plasma and measurement
The most reliable variable for determining nutrition status for vitamin D is the measurement of the 25-OH-D level in plasma.
At values of 25-OH-D between 10 and 40 ng/ml (Van den Berg et al., 1991). There are no signs of deficiency or even toxicity. However, individuals who do not expose themselves to sunlight can have much lower levels, such as 6 – 8 ng/ml. It has been verified that the concentration of 25-OH-D can instead reach 80 ng/ml in healthy adult subjects after prolonged exposure to the sun.
What Foods Have Vitamin D
needs and food sources Larn (the Reference Intake Levels of nutrients and energy of the Italian Society of Human Nutrition) establishes. The recommended intake of vitamin D for the Italian population. The adequate intake for children under one year of life is 10 μg per day. The recommended intake then rises to 15 μg per day up to age 75. When it further increases to 20 μg per day.
Most food sources of vitamin D are foods of animal origin. It is in fact found in some fish, cod liver oil, liver, eggs and milk, and derivatives. These foods contain the same form of vitamin D that is synthesized in the skin, vitamin D3 (or cholecalciferol). Few foods of plant origin contain vitamin D2 (or ergocalciferol).
Other possible sources of vitamin D are fortified foods (i.e., with added vitamin D) and dietary supplements. In the case of the latter, some studies suggest. That those based on vitamin D3 are more effective than their counterparts based on vitamin D2, beware, though: there is also a maximum tolerable level of vitamin D. In the first year of life, 65 μg per day from 1 to 3 years, 75 μg per day from 4 to 10 years, and 100 μg per day from 11 years of age.
Exceeding these doses, even this substance. Which is so useful for the well-being of the body, can become harmful. To health, exposing you to the risk of nausea, vomiting, constipation, lack. Of appetite, weakness, weight loss, confusion and disorientation, calcium deposits. In the tissues, soft tissue (e.g. in the heart and lungs), and kidney problems.
What Foods Have Vitamin D: supplements
Therefore, it is better to take supplements only after consulting your doctor to ascertain the actual need to resort. To their use and rely on, first of all, on the vitamin D present in food.
Here are 9 foods included among the healthiest foods with the highest vitamin D content.
1. Salmon trout and salmon two species are belonging. To the Salmonidae family very widespread on the banks of our fishmongers. Sources of omega-3 (fatty acids by the action anti-inflammatory known. For their beneficial effects on heart health) also contain good amounts of vitamin D.
In particular, 100 grams of salmon trout farm make 15.9 micrograms of vitamin D. Fresh salmon, on the other hand. Contains 10.9 μg per 100 grams, smoked salmon 17.1 μg per 100 grams, and canned salmon 15 μg per 100 grams.
- SwordfishSwordfish is also a source of omega 3 and vitamin D at the same time. The latter is present in doses of 13.9 μg per 100 grams of edible portion.
Being a large predator, swordfish carries with it a possible risk. Contamination by heavy metals that accumulate in the body can lead to serious side effects. Mercury, for example, is neurotoxic.
This problem also affects other fish containing vitamin D, such as salmon and tuna. For this reason, the general advice is not. To eat more than 150 grams of these types of fish per week.
- MackerelWith is 13.8 μg per 100 grams; it is another good source of vitamin D. Associated with omega 3 polyunsaturated fatty acids.
Vitamin D Foods
Compared to salmon, swordfish, and tuna, it has an advantage: it does not accumulate alarming doses of heavy metals.
- Herring and sardines vitamin D. Content of herring and sardines are similar: 4.2 μg in 100 grams for the former, 4.8 μg for the latter.
Also, in these cases, vitamin D is added to precious omega 3 fatty acids. And even these species, like mackerel, do not carry with them the risk of containing dangerous doses of heavy metals.
- Eggs need 2 whole eggs to take a little ‘more than 2 micrograms of vitamin D. To contain it is only the yolk, where it is present in concentrations equal to 5.4 μg per 100 g.
Unfortunately, eggs contain significant doses of saturated fat and cholesterol. According to the principles of the Mediterranean Diet, 2 to 4 can be eaten per week.
- TunaCompared to other fish, it contains much lower doses of vitamin D. Equal to 1.7 μg per 100 grams in the case of fresh tuna.
- The milk 100 grams of whole milk are 1.3 micrograms of vitamin D. Therefore. It is not the richest food in this precious vitamin. But it can contribute to its daily intake.
Vitamin D Nutrition Foods
Some cheeses and dairy products also contain a certain amount. There are some, for example, in whole yoghurt and feta.
- Bovine liver vitamin D content in the braised beef liver. Is not very different from that of whole milk: 1.2 μg per 100 grams. Together it also provides vitamin A, in doses of about 9.4 mg of retinol.
- Mushrooms, cocoa, and chocolate, depending. On the variables taken into consideration, 100 grams of mushrooms provide—about 0.2-0.4 μg of vitamin D in the form of vitamin D2.
It was once thought to be the only plant-based food source of vitamin D. Recent research has, however, revealed the presence of vitamin D2 also in cocoa and chocolate.
Being a fatty substance, cod liver oil promotes both. The absorption of vitamin D and that of vitamin A, both fat-soluble. It is no coincidence, in short, that it is one of the most popular ingredients among the most popular food supplements.
Spending time outdoors in the sun is the best way to get the daily dose of vitamin D you need. Adequate exposure during the summer allows you to stock up even for the winter.
Unfortunately, however, we must also deal with the need to protect the skin from the unwanted effects of ultraviolet rays. Furthermore, not everyone can expose themselves to sunlight. For the time necessary to synthesize enough vitamin D. Adequate nutrition makes it possible to avoid dangerous deficits. That can lead to problems such as rickets in children and osteoporosis in adults. In case you suspect a lack of vitamin D. It is good to consult with your doctor who, in case of need, will be able to indicate the most suitable food supplement for your case.