Many people around the world today are deficient in vitamin D. This is often due to poor nutrition and lack of access to sunlight.
Vitamin D is one of the fat-soluble vitamins that our body needs to grow and strengthen bones. Vitamin D prevents problems such as osteoporosis by controlling the balance of calcium and phosphorus, increasing the absorption of phosphorus and calcium from the intestines and reducing excretion by the kidneys.
Foods and snacks that are sources of vitamin D.
Very few foods in nature contain vitamin D are. Among these foods, fatty fish (such as salmon , salmon , tuna, and mackerel) and fish oil are the best sources of vitamin D. Vitamin D is also small amounts in beef liver, cheese and egg yolk eggs there. The vitamin in these foods is in the form of vitamin D3 and its metabolite is 25 (OH) D. Some fungi produce different amounts of vitamin D2. There are also fungi fortified with vitamin D2 that have been subjected to UV-controlled conditions.
In the American diet , fortified foods provide the most vitamin D. For example, almost all milk producers in the United States voluntarily fortify milk with 120 units (IU) of vitamin D per cup of milk.
In Canada, milk is fortified with about 35 to 40 units of vitamin per 100 milliliters. This figure for vegetable butter is more than 530 units per 100 grams. According to the IRNA news agency , quoting Zahra Abdollahi, director general of the Nutrition Improvement Office of the Ministry of Health, Treatment and Medical Education, in our country, milk is enriched with vitamin D. Therefore, by consuming a glass of milk enriched with this vitamin, 30% of people’s daily needs for this vitamin will be met.
Animal foods produce some vitamin D in the form of 25 (OH) D. Apparently, this amount is about 5 times stronger than the main vitamin in increasing the serum concentration of 25 (OH) D. Research has shown that taking serum 25 (OH) D in meat, poultry, turkey and eggs can increase the estimated amount of vitamin D in food by 2 to 18 times, depending on the type of food.
At present, 25 (OH) D is not reported when reporting the content of vitamin D in food.
1. Salmon fish
Salmon is a popular high-fat fish and a rich source of vitamin D. 100 grams of salmon contains about 361 to 685 units of vitamin D. But it is not clear whether this amount of vitamin D is for marine fish or farmed fish. It may not matter at all, but it can make a big difference.
The results of a study showed that fish naturally caught from the sea and rivers contain an average of 988 units of vitamin D per 100 grams. This provides 247% of the daily requirement index (RDI) for vitamin D.
Some studies have shown even higher percentages of this vitamin in natural fish, amounting to 1,300 units per serving. Farmed fish provide on average only 25% of this amount. However, each serving of farmed salmon provides 250 units of vitamin D, which is equivalent to 63% of our daily requirement of this vitamin.
2. Herring and sardines
Herring is consumed all over the world. This fish is served in raw, canned, smoked and salty forms. This fish is also a rich source of vitamin D. Fresh Atlantic herring contains 1,628 units of vitamin D per 100 grams. This is four times the daily requirement of vitamin D.
If you do not like fresh fish, you can eat salty herring, which is also a source of vitamin D. For every 100 grams of salted herring, there are 680 units of vitamin D, which is equivalent to 170% of the RDI index.
Salted fish also contains large amounts of sodium, which some people consume in excess.
Sardines are another type of herring that is high in vitamin D. Each serving of this fish receives 272 units of vitamin D, which is 68% of the RDI index. Other types of fatty fish are also good sources of vitamin D. Lozenges or halibut (which is a large flatfish) contain 600 units per 100 grams and mackerel contain 360 units of vitamin D per 100 grams.
3. Fish liver oil
Fish liver oil is one of the most popular supplements. If you do not like fish, you can use fish liver oil to provide the specific nutrients your body needs that can be found in other hard sources.
Each teaspoon of fish liver oil contains 450 units of vitamin D. On this account, this nutrient is one of the best sources of this vitamin. Fish liver oil has long been used to prevent and treat vitamin D deficiency in children.
Cod liver oil is also an excellent source of vitamin A is. Just one teaspoon of it contains 90% of the RDI index of vitamin A. However, taking too much vitamin A can be harmful and dangerous. So it is better to be careful in consuming fish liver oil and do not consume more than your body needs.
It also contains omega-3 fatty acids, which are deficient in many people.
4. Canned tuna
Many people like canned tuna because of its mild taste and smell. In addition, because canned fish can be stored at home for longer, there is a strong desire to eat it. It is also cheaper than fresh fish.
Canned tuna contains 236 units of vitamin D per 100 grams. This is more than half of the RDI index. This canned food also contains vitamin B3 and vitamin K.
Unfortunately, canned tuna contains a toxin called methylmercury, which is found in many types of fish. If this toxin spreads in the blood, it can cause serious problems for human health. However, some types of fish are less dangerous than others. Light tuna is a better choice than white tuna and consuming it up to 170 grams per week is useful and has no side effects.
Shrimp is one of the most popular types of crustaceans. Unlike other high-fat sources of vitamin D, shrimp are very low in fat. Despite this, this nutrient contains a lot of vitamin D. There are 152 units of vitamin D per 100 grams of shrimp, which is equivalent to 38% of the RDI index.
Shrimp also contain omega-3 fatty acids, but this amount is lower than other substances that are high in vitamin D. There is also 152 mg of cholesterol per 100 grams of shrimp, which is a significant amount. However, this should not worry you. Many recent studies have shown that dietary cholesterol intake does not have much effect on blood cholesterol levels . Even one of the most authoritative sources for diet planning has raised the ceiling of cholesterol consumption and stated that high cholesterol consumption is not important.
6. Egg yolks
The good news for people who do not like fish: Seafood is not the only source of vitamin D. Whole eggs are a good source; It is also a delicious and nutritious food. Most egg protein is found in egg whites, but fats, vitamins and minerals are found mainly in the yolk.
The yolk of a typical industrial egg contains 18 to 39 units of vitamin D, which is not too much. But the vitamin D in the eggs of local chickens raised in pastures and under sunlight is three to four times higher.
In addition, eggs from chickens fed a fortified vitamin D diet are high in vitamin D. It is said that this amount reaches 6,000 units per yolk.
Eating local eggs or industrial eggs high in vitamin D can help meet your daily requirement.
With the exception of fortified foods, mushrooms are the only natural source of vitamin D. Fungi, like humans, can produce this vitamin if exposed to ultraviolet light. Fungi produce vitamin D2 and animals produce vitamin D3. Although vitamin D2 helps raise blood levels of vitamin D, it is not as effective as vitamin D3.
However, wild mushrooms are an excellent source of vitamin D2. In fact, some types of mushrooms have up to 2,300 units of this vitamin per 100 grams.
Cultivated fungi, on the other hand, often grow in the dark and contain much less vitamin D2.
However, certain brands grow the fungus under ultraviolet light. Each 100 grams of these fungi can provide 130 to 450 units of this vitamin.
8. Cereals and oatmeal
Certain cereals and instant breakfast with grits and oatmeal with vitamin D fortified. Half a cup of this substance can provide 55 to 154 units of vitamin D needed by the body, which is equivalent to 39% of the RDI index. Enriched cereals and oatmeal have less vitamin D than natural sources, but can be a good way to increase your intake of this vitamin.
To get the vitamin D your body needs, spend time outdoors in the sun. Of course, exposure to sunlight is not possible for many people. Getting vitamin D through diet is difficult, but not impossible. The nutrients mentioned in this article were some of the sources of the most vitamin D. Eating these foods rich in vitamin D can meet your need for this very important nutrient.
Foods fortified with vitamin D.
In 1930, a milk fortification program was launched in the United States to combat rickets or osteoporosis . Rickets was a major public health problem. Other dairy products such as cheese and ice cream are not usually fortified. Breakfast cereals, some brands of orange juice, yogurt and butter contain extra vitamin D. Vegetable milks such as soy milk , almond milk and oat milk are often fortified with vitamin D in similar amounts to fortified cow’s milk (about 120 units of vitamin D per cup of milk). The label on the food indicates the actual amount of its contents.
The agency Mshrqnyvz , the research that has been done in Iran, in 100 patients with bone fractures, 90 cases of vitamin D deficiency , respectively. In other studies conducted in the country, 2 to 3% of people were deficient in vitamin D. On this account, the use of supplements as a food fortifier is necessary.
In both the United States and Canada, powdered milk is fortified with vitamin D. That’s 40 to 100 units per 100 kcal in the United States, and 40 to 80 units per 100 kcal in Canada. The US Food Information Center provides a comparable list of foods containing vitamin D based on nutrient content and name by examining many foods. Although more and more foods are being tested for vitamin D content, a simpler and faster way to measure the amount of vitamin D in foods is needed.
Today, fortified foods can help people who are unable to get the vitamins, minerals, and nutrients they need from natural sources. In the following, we will introduce foods enriched with vitamin D.
9. Breakfast cereal
Natural sources of vitamin D are limited, especially if you are a vegetarian or do not like fish. Fortunately, some foods that do not naturally have vitamin D are fortified.
10. cow milk
Cow’s milk, the milk that most people drink, is naturally a good source of many nutrients, including calcium , phosphorus, and riboflavin. In some countries, cow’s milk is fortified with vitamin D. In each cup (237 ml) of cow’s milk, there are 130 units or 33% of the RDI index.
11. Soy milk
Because almost all sources of vitamin D are found in animal products, vegetarians are at risk for vitamin D deficiency. That’s why plant-based milks, such as soy milk, are fortified to contain vitamin D and vitamins and all the minerals found in cow’s milk.
One cup (equivalent to 237 ml) of soy milk usually contains 99 to 119 units of vitamin D. This figure is 30% of the RDI index.
12. Orange juice
About 75% of people worldwide suffer from lactose intolerance. 2 to 3% of this population is also allergic to milk. For this reason, some countries enrich orange juice with vitamin D and other nutrients such as calcium. With a cup of fortified orange juice (237 ml) for breakfast, you can start your day with 142 units of vitamin D or 36% of the RDI index.
Most people get at least some of the vitamin D they need from sunlight . Type B ultraviolet light, ie UVB with a wavelength of 290 to 320 nm, penetrates the unprotected skin. 7- Hydrocholesterol then changes the skin into a precursor of vitamin D3, which is also converted to vitamin D3.
Season, time of day, length of day, cloud cover, time limit , melanin content of skin and sunscreen are some of the factors that affect UV radiation and vitamin D production. You may be surprised that latitude does not affect the average serum 25 (OH) D in the population. Even at higher northern temperatures, with exposure to sunlight in spring, summer, and fall, there are many opportunities for vitamin D to form and store in the liver and fat.
Sunscreen and sunlight from behind the glass
Fully cloudy weather reduces UV energy by up to 50% and shade from severe pollution by up to 60%. Type B UV light does not pass through the glass; For this reason, it does not produce vitamin D in the sun at home or behind windows. Sunscreen with a sun protection factor (SPF) of 8 or more disrupts the production of vitamin D. In practice, however, people do not use enough sunscreen regularly or cover the entire skin exposed to sunlight . So even when sunscreen is used, the skin produces some vitamin D.
It is difficult to prepare a general guide and determine the time required for sun exposure in order to maintain a sufficient amount of vitamin D. Some researchers recommend that you expose yourself to sunlight at least twice a week for 5 to 30 minutes between 10 a.m. and 3 p.m. Expose your face, arms, legs and back to sunlight without sunscreen to get enough vitamin D.
Solarium boards (tanning)
Balanced use of solarium boards is also effective. These boards emit 2 to 6 percent of type B UV light. People who are less exposed to sunlight need to include adequate sources of vitamin D in their diet or take supplements to get the recommended amount of vitamin.
Unlike sunlight, care must be taken when exposing the skin to ultraviolet light from tanning boards. Annual UV radiation in the United States causes more than 1.5 million people to develop skin cancer and 8,000 to die from metastatic melanoma . According to Ardabil University of Medical Sciences and Health Services , skin cancer is one of the 10 most common cancers in Iran. Cumulative lifelong UV damage to the skin is responsible for some age-related dryness and other changes in appearance. For this reason, it is recommended that people who are exposed to the sun take protective measures such as using sunscreen.
Assessing the amount of vitamin D needed can not determine the amount of sun exposure; Because in this case, there is a concern about cancer . There is no research to show that the synthesis of vitamin D induced by ultraviolet light occurs without increasing the risk of skin cancer.
Vitamin D is available in supplements and fortified foods in two forms: D2 or ergocalciferol and D3 or cholecalciferol. The two differ chemically only in the structure of the side chain.
D2 is produced by ultraviolet radiation from ergosterol in yeast. D3 is made by irradiation with 7-dehydrocholesterol from lanolin and chemical change from cholesterol . These two vitamins work the same way based on their ability to treat rickets. In fact, most of the metabolism and activity of these two vitamins are similar. Both forms of vitamin (as well as vitamin D in food and skin synthesis) effectively increase serum 25 (OH) D. No definite conclusion can be drawn about the different effects of these two types of vitamin D. But most evidence suggests that vitamin D3 increases serum 25 (OH) D levels to a greater extent and maintains these higher levels more than vitamin D2, even if both forms are well absorbed in the gut.
It is recommended that infants receive 400 units of vitamin D supplements shortly after birth. They should continue to take supplements until they are weaned. At this time, they consume more than 1 liter of powdered milk enriched with vitamin D or whole milk daily. Similarly, all infants who are not breastfed and who consume less than 1 liter of vitamin D-fortified formula or milk daily should receive 400 units of vitamin D supplementation daily. Children and adults who do not get 400 units of vitamin D a day through vitamin-fortified milk or foods should also take this supplement. Recent sources suggest, however, that a daily dose of 600 vitamin D supplements is recommended for children and adults.
Vitamin D intake
Vitamin D is unique in that it can be absorbed by both food and sunlight. However, about 50% of the world’s population does not get enough sunlight, and many of these people are deficient in vitamin D. This is partly because people spend most of their time indoors and outdoors, apply sunscreen, and eat large amounts of fast food that is low in vitamin D.
Vitamin D is usually obtained from both food and supplements. The average daily intake of vitamin D for men, depending on the stage of life and only through food, is between 204 and 288 units per day. This figure is between 144 and 276 units per day for women. When supplements are taken, these amounts increase dramatically (37% of the US population takes vitamin D supplements). The greatest increase in supplementation is in older women. In women between the ages of 51 and 70, the average daily intake of vitamin D is 156 units per day, but with a supplement it reaches 404 units. For women over 70, the relevant figures are 180 to 400 units per day.
Consumption based on serum concentrations of 25 (OH) D
It is difficult to estimate vitamin D intake from foods and diets based on serum 25 (OH) D concentrations. One reason is that instead of comparing individual information, the comparison is based on the group average. The next point is that sun exposure may affect vitamin D status; So the serum concentration of 25 (OH) D is usually higher than the amount predicted based on vitamin D intake alone.
According to reports, the average level of 25 (OH) D in all gender groups in the US population is 22.4 ng / ml. The highest dose (71.4 ng / ml) is for girls 1 to 3 years old, and the lowest dose (22.6 ng / ml) is for women 71 years and older. Young people usually have higher levels of vitamin D than older people, and men than women.
Over the past 20 years, the average serum concentration of 25 (OH) D in men has decreased slightly, which may be due to weight gain, reduced milk consumption and excessive use of sunscreen when going out.
How do you get the vitamin D you need? How much do you care about the presence of this vitamin in your diet or supplements? Do you suffer from problems due to vitamin D deficiency? Which sources of vitamin D and which methods do you think are most effective?