11 Foods Rich in Vitamin D

Contents:

• Is it true that vitamin D is not a vitamin?
• Why is vitamin D called a vitamin?
• Why do we lack vitamin D?
• Which vitamin D is best?
• How much vitamin D do you need?
• Which foods are high in vitamin D?
• Is it possible to get enough vitamin D from food alone?
• What is the difference between vitamin D supplements and vitamin D supplements?

Is it true that vitamin D is not a vitamin?

Vitamin D is synthesized in our body. It is formed in the skin under the influence of sunlight and then is activated in the liver and kidneys. It is important to note that vitamin D is not a regular vitamin; its effects are more similar to a hormone. Let's look at its action and compare it with the functions of other vitamins. Vitamin D plays a key role in maintaining health, influencing the metabolism of calcium and phosphorus, which is important for strong bones and teeth. It also helps normalize immune function and can reduce the risk of developing a number of diseases. It is important to maintain optimal levels of vitamin D in the body, which can be achieved through sun exposure, as well as with special supplements and foods rich in this substance.

Why is vitamin D called a vitamin then?

Active vitamin D, having the properties of a hormone, is scientifically called the D-hormone.

Vitamin D is the historical name of an important substance that plays a key role in maintaining the health of bones and cartilage. In 1922, the American scientist Elmer Werner McCollum isolated it from fish oil, suggesting that it helps in the prevention and treatment of rickets in children. McCollum called this compound "calcitriol" because it helps increase calcium levels in the blood. In addition, he also used the name vitamin D, having discovered it in various foods. Later, it was discovered that our body is able to independently synthesize this substance under the influence of sunlight, which makes it even more important for health. Vitamin D is essential for maintaining the immune system and overall well-being, so it's important to monitor its levels. To date, research has shown that vitamin D affects over 40 different tissues in the body. This discovery underscores its importance in maintaining health and the normal functioning of various systems. Vitamin D plays a key role not only in maintaining strong bones but also in regulating immune function and preventing a number of diseases. Its effects on tissues and cells can have a significant impact on overall health. Therefore, it is important to monitor your vitamin D levels and adjust your intake through food or supplements if necessary.

• helps you lose weight [3];
• improves depression [4];
• strengthens teeth and oral health [5];
• suppresses tissue inflammation [6];
• protects cells from the harmful effects of free radicals [7];
• enhances anti-infectious defenses [8];
• stimulates the production of female sex hormones [2].

A sufficient level of calcitriol significantly reduces the risk of developing various diseases and infections.

Why We Don't Have Enough Vitamin D

About 1 billion people worldwide suffer from vitamin D deficiency (hypovitaminosis D). This is surprising, as vitamin D is known to be synthesized in the skin under the influence of sunlight. The ultraviolet radiation we receive from the sun provides approximately 80% of the daily requirement for this important vitamin. However, many factors, such as lifestyle, geographic location, and climate conditions, can significantly reduce the amount of sunlight available to the skin, leading to vitamin D deficiency.

Vitamin D is one of the most important vitamins, however Getting enough vitamin D can be challenging for several reasons. Factors such as sunlight exposure, time of year, geographic location, and sun protection influence vitamin D synthesis in the skin. A vitamin D deficiency can lead to various health problems, including weakened bones and immune system. Therefore, it's important to monitor your vitamin D levels and, if necessary, consider getting it through food or supplements.

• Geography. To form the "sunshine" vitamin, medium-wave ultraviolet rays (UVB) are needed, which do not reach the Earth's surface at all latitudes - the farther from the equator, the fewer UVB photons [12], [13]. Thus, Russia is not a very sunny country.
• Air pollution. Industrial emissions, smog and dust block the UV spectrum.
• Age. The intensity of vitamin D synthesis in the skin decreases by 75% in people over 65 years of age.
• Skin color. Dark skin produces six times less vitamin D, because the skin pigment melanin, responsible for skin color, competes for the opportunity to absorb medium-wave UV rays [14], [1]. And the darker the skin, the more time you need to spend in the sun for your body to synthesize vitamin D.

We often worry about exposure to direct sunlight because ultraviolet B radiation does not penetrate glass, clothing, or even high-protection sunscreens like SPF 15. It's important to remember that sun protection is necessary not only outdoors but also indoors where the sun's rays can reach your skin. Using sunscreen and wearing the right clothing can help prevent the negative health effects associated with ultraviolet radiation.

Using sunscreen is essential even in winter. Getting the daily requirement of vitamin D requires prolonged sun exposure, which can cause mild skin redness. This is not only dangerous, as it can cause sunburn, but also increases the risk of developing skin cancer in the future. Therefore, it is important to use sunscreen to protect your skin from the potentially harmful effects of ultraviolet rays.

Which vitamin D is best?

There are seven compounds with a similar chemical structure that are grouped under the general term "vitamin D". Most often, this name refers to the two main forms of vitamin D - D2 and D3. These forms differ in their provitamins, that is, the original substances, but have a common property - inertness. Vitamin D plays a key role in maintaining health, influencing metabolism and the immune system.

In order for provitamins to be converted into active vitamin D (calcitriol), they undergo several stages of metabolism in the body. This process includes the conversion of provitamins into vitamin D, which then undergoes further activation. The complete pathway from provitamins to the active form of vitamin D can be represented as follows:

• From plants: provitamin ergosterol → D2 (ergocalciferol) → liver → kidneys → active vitamin D.
• From animal products and from the sun: provitamin 7-dehydrocholesterol → D3 (cholecalciferol) → liver → kidneys → active vitamin D.

Vitamin D2 is converted into its active form more slowly than vitamin D3. Therefore, vitamin D3 is more often found in vitamin supplements. However, after metabolic conversion, both forms of vitamin D have similar effects on metabolism in the body.

How much vitamin D should you get?

Rospotrebnadzor establishes certain standards and regulations that govern various aspects of public health and safety. These standards are aimed at protecting citizens from harmful factors and ensuring a high level of public health. It is important to comply with these requirements to minimize risks and prevent disease. Systematic compliance with Rospotrebnadzor standards contributes to the creation of a safe and healthy living and working environment.

• for adults - 15 mcg per day, which is equal to 600 IU;
• for people over 65 years old - 20 mcg per day (800 IU);
• for children - from 10 to 15 mcg per day (400-600 IU).

The dosage of vitamin D is indicated in international units (IU) for historical reasons. Vitamin D was originally used to prevent rickets, and the emphasis was not on the quantity of the substance, but on its biological activity, which prevents this disease. This is why its effectiveness is assessed in international units. This allows us to more accurately determine the required dose to achieve the desired therapeutic effect, based on scientific research and clinical indications.

1 IU of vitamin D corresponds to 0.025 mcg of vitamins D2 or D3. This means that 1 mcg of inactive forms of vitamin D2 and D3 is equivalent to 40 IU of active vitamin D. Understanding the correct dosage of vitamin D is important for maintaining health, as this vitamin plays a key role in metabolism and strengthening the immune system.

Which foods are high in vitamin D

It's important to note that vegetables and fruits do not contain vitamin D. However, our list features 11 foods rich in this vitamin, including several plant sources. Vitamin D plays a key role in maintaining health, helping to strengthen bones and the immune system. Learn about the best sources of this important nutrient and add them to your diet for complete nutrition.

We present a detailed review of each of our products. We will focus on the key characteristics and features that make them unique. Each product has been developed with the needs of users in mind to ensure maximum effectiveness and ease of use. You'll be able to learn about the benefits, functionality, and uses of each product, helping you make an informed choice.

Fish oil as a food product has its roots in the Viking Age. The indigenous peoples of Scandinavia traditionally used cod liver extract, producing oil from it or frying it. This product played a significant role in the diet of northern peoples, providing them with important nutrients. Fish oil is rich in omega-3 fatty acids, making it valuable for maintaining health. In the modern world, it continues to be popular due to its beneficial properties and ability to improve overall health.

Until 1970, fish oil was a mandatory dietary supplement for children in the USSR, as it helped replenish essential fatty acids, as well as vitamins D and A. However, fish oil contained inconsistent amounts of vitamin D and often contained high levels of vitamin A, an excess of which can be toxic. With technological advances, pesticides and other toxins accumulated in the liver of cod fish entered water bodies. Currently, fish oil is extracted from cod muscle, which reduces the vitamin D content of the product. Therefore, it is important to pay attention to the source and composition of fish oil to ensure optimal nutrient intake.

Cod liver is a rich source of vitamin D, making it an excellent alternative to both fresh fish and less palatable fish oils. However, it is important to keep in mind that this product is high in calories and fat, so it is not recommended to consume it too often. When choosing canned fish, it's important to pay attention to the quality of the product, as elevated levels of arsenic are sometimes found in cod liver.

Vitamin D content varies significantly between wild and farmed salmon. Wild salmon from North Atlantic waters has the highest levels of vitamin D. The level of this vitamin in farmed salmon depends on its diet. Fish fed microalgae accumulate more nutrients, including vitamin D, making them healthier. Choosing between wild and farmed salmon can significantly impact vitamin D intake, which is important for the immune system and bone health.

The Union of Pediatricians of Russia provides information on the vitamin D content of salmon. This important vitamin plays a key role in maintaining health, especially in children. Salmon is one of the best sources of vitamin D, making it a beneficial dietary product. Regular salmon consumption can help improve vitamin D levels, which in turn has positive effects on the immune system and overall health. Don't miss a can of sardines on your next grocery run—they can provide up to 50% of your daily vitamin D requirement and have a positive effect on brain function. A study conducted by scientists at the University of Greifswald in Germany found a link between vitamin D levels and brain aging. An analysis of magnetic resonance imaging (MRI) scans of 1,865 participants showed that vitamin D deficiency can accelerate brain aging, highlighting the importance of this vitamin for maintaining cognitive function and overall health. Including sardines in your diet can be a simple and effective way to boost your vitamin D levels and improve brain health.

Canned tuna has the same high nutritional value as farmed salmon. One can of canned tuna contains about a third of the daily value of vitamin D, making it an excellent source of this important vitamin. Canned tuna is not only convenient to eat but also beneficial for maintaining health. It can be included in a variety of dishes, helping to obtain essential nutrients. The yolks of eggs collected in summer can contain twice as much vitamin D as winter eggs. This is confirmed by a study conducted by specialists from the Institute of Agricultural and Food Sciences in Germany. To increase vitamin D levels in eggs, laying hens began to be kept outdoors in the sun. As a result, the concentration of vitamin D in dry matter increased by 3 mcg, which corresponds to 120 international units (IU) per 100 grams of product. Shiitake mushrooms, champignons, and oyster mushrooms contain the plant provitamin ergosterol. When exposed to sunlight, it is converted into vitamin D2. To increase the vitamin D2 content of mushrooms, they are exposed to ultraviolet light during cultivation, which triggers this reaction. The amount of vitamin D2 accumulated in mushrooms depends on the duration of exposure and other growing conditions. Proper processing methods and growing conditions can significantly increase vitamin D2 levels, making these mushrooms a valuable source of this important vitamin.

In many countries, the vitamin D content in milk reaches 400 IU per liter, which is approximately 75% of the daily requirement for an adult. To produce this fortified milk, cows are exposed to artificial ultraviolet light for several hours. This significantly increases the vitamin D level in the product, making it a valuable source of this essential nutrient. Fortified milk may be especially beneficial for people who don't get enough vitamin D from sunlight or food.

The United States Department of Agriculture (USDA) conducted a study to determine the amount of vitamin D in one cup (230 ml) of whole and plant-based milk. Vitamin D plays an important role in maintaining bone and immune health, so knowing its content in popular beverages can help consumers make more informed choices. Whole milk is a common source of vitamin D, while plant-based milks are becoming increasingly popular among those who follow a vegan diet or are lactose intolerant. Assessing the vitamin D content of these products can help people balance their diets and ensure they get the necessary amount of this important vitamin.

According to the United States Department of Agriculture, plain yogurt made from whole cow's milk contains 31 IU of vitamin D. Fortified yogurt can contain up to 200 IU. Researchers from Belgium conducted an interesting study that showed that consuming one yogurt (125 g) daily, fortified with calcium (400 mg) and vitamin D (200 IU), can help prevent fractures caused by bone loss. This positive effect is especially important for people over 70, whose risk of osteoporosis and fractures increases significantly. Eating yogurt as a source of vitamins and minerals can be an important component of a healthy diet and strengthening the skeletal system.

In 2012, the European Commission on Dietetic Products, Nutrition and Allergy (EFSA) approved the use of ultraviolet-irradiated yeast as a new food ingredient. This yeast is used in the production of bread and pastries. 100 grams of these products contain 200 IU of vitamin D2, making them a valuable source of this essential vitamin. Consuming products containing irradiated yeast can help improve vitamin D levels in the body, which is especially important in regions with low sunlight. Cocoa beans used to make chocolate contain a certain amount of fungi. These fungi are capable of accumulating ergosterol, a precursor to vitamin D2. Thus, chocolate may contain natural sources of this important vitamin, which adds additional value to the product.

Julia Kühn, a researcher at the Institute of Agricultural and Food Sciences in Germany, and her colleagues believe that drying cocoa beans in the sun promotes the conversion of ergosterol to vitamin D2. As a result, the vitamin D2 content of dark chocolate can vary from 1.90 to 5.48 μg, which corresponds to 76–216 international units (IU) per 100 grams of product. These data highlight the potential benefits of dark chocolate as a source of vitamin D2, making it an interesting product for increasing the level of this vitamin in the diet. Research in this area opens new horizons for the use of chocolate not only as a dessert, but also as an element of a balanced diet.

Is it possible to get enough vitamin D from food alone?

Even in an optimally balanced diet, there is often a vitamin deficiency of at least 20% of the daily requirement. To compensate for this deficiency, it would be necessary to double the amount of food consumed. In addition, for the effective absorption of vitamin D, the diet must contain fat, since this vitamin is fat-soluble. However, excessive fat consumption can lead to excess weight gain. Therefore, in case of hypovitaminosis, relying solely on foods rich in vitamin D is inadvisable. Doctors strongly recommend taking additional vitamin supplements to fully replenish the deficiency.

What is the difference between vitamin D dietary supplements and a vitamin supplement?

According to the requirements of GOST R 57106-2023, vitamin and mineral complexes are divided into two main groups. These complexes play an important role in maintaining health and providing the body with essential nutrients. Each group is aimed at meeting the body's different needs for vitamins and minerals, which helps improve overall health and prevent nutrient deficiencies. It's important to consider these classifications when choosing vitamin and mineral supplements to optimize your diet and strengthen your immune system.

• The first contains few vitamins, and their amount does not exceed the daily requirement,
• the second may contain the daily requirement or an amount several times greater.

There are vitamin therapy products that contain vitamins in doses significantly exceeding the daily requirement. These products can be effective in correcting vitamin deficiencies and maintaining health. It's important to remember that such products should be used under the supervision of a physician to avoid possible negative consequences from excess vitamins.

To identify a vitamin deficiency and select the appropriate product, it's important to consult a physician. A specialist will conduct the necessary tests and assess your health, which will help determine which vitamins or minerals need to be replenished. Consulting a doctor ensures the correct choice of drug and minimizes the risk of side effects.