Shedding Light on the Sun Vitamin: Unveiling the Hidden Benefits of Vitamin D

Vitamin D

Vitamin D is a fat-soluble vitamin that acts as a steroid hormone. This vitamin is unique because it can be made in the skin from exposure to sunlight. Apart from sun exposure, it can also be achieved through diet from certain foods like:

• Cod liver oil
• Salmon
• Swordfish
• Tuna fish
• Fortified orange juice
• Fortified dairy and plant milk
• Sardines
• Egg yolk
• Fortified cereals

Vitamin D deficiency (VDD) is a prevalent condition affecting a significant portion of the global population annually. It is a common issue observed across various age groups. The primary causes of VDD in modern times are attributed to low levels of outdoor activity due to lifestyle factors and environmental influences like air pollution. Additionally, obesity has been found to be associated with VDD.

Anticonvulsants, as well as pharmaceuticals used to treat AIDS and HIV, put patients at risk of VDD because they speed up the breakdown of 25(OH)D and 1,25(OH)2D. Patients with chronic granuloma-forming disorders (like sarcoidosis, tuberculosis, and chronic fungal infections), some lymphomas, and primary hyperparathyroidism who have increased metabolism of 25(OH)D to 1,25(OH)2D are also at high risk for VDD.

In order to produce the same quantity of vitamin D as someone with white skin, someone with a naturally dark skin tone needs to be exposed to the sun for at least three to five times longer.

Emerging research indicates the probable role of this sunlight vitamin against cancer, heart disease, fractures and falls, autoimmune illnesses, influenza, type-2 diabetes, and depression.

Activation of sunshine vitamin in the body

The ultraviolet B (UVB) rays of the sun interact with a protein in the skin called 7-DHC, turning it into vitamin D3. Human beings cannot produce vitamin D2.

Vitamin D from the skin or diet is physiologically inactive and must be hydroxylated to 25(OH)D in the liver by the vitamin D-25-hydroxylase (25-OHase). To create the biologically active form of vitamin D i.e., 1,25-dihydroxy-vitamin D3, 25(OH)D must be hydroxylated again in the kidneys by the 25(OH)D-1-OHase (CYP27B1).

Roles of vitamin D in the human body

1,25-dihydroxy-vitamin D3 stimulates the absorption of calcium in the human intestine. Only 10-15% of dietary calcium and about 60% of phosphorus are absorbed without vitamin D. Sufficient vitamin D increases calcium and phosphorus absorption by 30-40% and 80%, respectively.

Cancer: 1,25-dihydroxy-vitamin D3 help in the inhibition of cellular proliferation and inducing terminal differentiation, inhibiting angiogenesis (Formation of new blood vessels.

Heart disease: Protective action of sunshine vitamin on the heart may be due to its role in the renin-angiotensin hormone system, anti-inflammatory role, or the direct action of vitamin d on the cell of the heart and blood vessels.

Hypertension: As per the research, age-related hypertension was low in people with enough vitamin D. Apart from that, arterial hypertension was also common in people with sunshine vitamin deficiency. Antihypertensive action of vitamin D is based on renoprotective benefits, RAAS suppression, favorable calcium homeostasis effects, including the avoidance of secondary hyperparathyroidism, and vasculoprotective effects.

Type 2 diabetes: As per the trial done on non-diabetic people aged 65 and older, a low rise in fasting plasma glucose level was seen in individuals who took 700 IU of vitamin D (plus calcium) compared with a placebo.

Depression: In a Norwegian study of obese participants, those who received a high dose of vitamin D (20,000 or 40,000 IU weekly) had significantly better scores on the depressive symptom scale after a year than those who received a placebo.

Cognitive impairment: As per the study done on the Italian-based population, low levels of sunshine vitamin were associated with substantial cognitive decline.

Fracture: Vitamin D helps the body to absorb calcium, which helps in the maintenance of bone health. Numerous studies have linked low vitamin D levels to an increased risk of fractures and fall in older persons.

Local 1,25(OH)2D synthesis may be responsible for regulating up to 200 genes. This Vitamin also plays a role in regulating the immune system.

Recommended dietary intakes of vitamin D for patients at risk for vitamin D deficiency (VDD)

Fig 2: Recommended dietary intake for patient at risk of VDD

Tips to maintain adequate vitamin D levels in the body

To maintain adequate levels of vitamin D in your body, consider the following tips:

1. Get regular sunlight exposure: Sunlight is a natural source of 1,25-dihydroxy-vitamin D3. Spend time outdoors, especially during midday when the sun’s rays are the strongest. Aim for 10-30 minutes of sun exposure on your face, arms, and legs a few times a week. Keep in mind that the ability to produce vitamin D from sunlight varies depending on factors such as geographical location, season, skin color, and use of sunscreen.
2. Consume vitamin D-rich foods: Include foods that are naturally rich in vitamin D in your diet. Fatty fish like salmon, mackerel, and sardines, as well as cod liver oil, are excellent sources of 1,25-dihydroxy-vitamin D3. Other food sources include fortified dairy products (milk, yogurt, and cheese), fortified plant-based milk alternatives, eggs, and mushrooms.
3. Consider fortified foods: Check food labels for products that are fortified with vitamin D, such as cereals, orange juice, and some types of bread. These fortified foods can contribute to your vitamin D intake, especially if natural food sources are limited.
4. Include dietary fat: Vitamin D is a fat-soluble vitamin, so consuming some dietary fat alongside vitamin D-rich foods can enhance its absorption. Pair foods like fatty fish with healthy fats such as olive oil, avocado, or nuts.
5. Consult a healthcare professional: If you have specific concerns about your vitamin D levels, it is advisable to consult with a healthcare professional who can assess your individual needs and recommend appropriate supplementation if necessary. They can also perform a blood test to measure your vitamin D levels.

Remember, it’s important to strike a balance between sun exposure, dietary sources, and, if needed, supplementation to maintain optimal vitamin D levels. Consultation with a healthcare professional can help determine the best approach based on your individual circumstances.

Reference

Amrein, K., Scherkl, M., Hoffmann, M., Neuwersch-Sommeregger, S., Köstenberger, M., Tmava Berisha, A., Martucci, G., Pilz, S., & Malle, O. (2020). Vitamin D deficiency 2.0: an update on the current status worldwide. European Journal of Clinical Nutrition, 74, 1–16. https://doi.org/10.1038/s41430-020-0558-y

Jones, T. (2018, September 12). 9 Healthy Foods That Are High in Vitamin D. Healthline; Healthline Media. https://www.healthline.com/nutrition/9-foods-high-in-vitamin-d

Nair, R., & Maseeh, A. (2012). Vitamin D: The “sunshine” vitamin. Journal of Pharmacology & Pharmacotherapeutics, 3(2), 118–126. https://doi.org/10.4103/0976-500X.95506

Pilz, S., Zittermann, A., Trummer, C., Theiler-Schwetz, V., Lerchbaum, E., Keppel, M. H., Grübler, M. R., März, W., & Pandis, M. (2019). Vitamin D testing and treatment: a narrative review of current evidence. Endocrine Connections, 8(2), R27–R43. https://doi.org/10.1530/ec-18-0432

yeubaan. (2022, December 8). Balanced Diet And Plate Portioning – Yeu Baan. Yeubaan.com. https://yeubaan.com/balanced-diet-and-plate-portioning/