We all love the long, shiny, summer days when the sun is shining, and it’s warm outside. And catching the sun is, in fact, the cause for these pleasant feelings!
When exposed to sunlight, our body forms vitamin D, which is essential for a healthy immune system, healthy teeth, and strong bones.
This vitamin allows the absorption of phosphorus and calcium and prevents various diseases. Yet, it is not possible to get the necessary sunlight during the entire year, so you should try to optimize the vitamin D levels through dietary sources.
When exposed to sunlight, the skin creates Vitamin D3 (cholecalciferol) within 15 minutes in the case of fair skin, and up to 2 hours, if your skin is darker.
Therefore, you do not need to burn the skin to optimize your vitamin D levels. Usually, the production of this vitamin is from direct exposure to large body areas, like the back.
The amount of the consumed vitamin D depends on:
- Time of day: It is best to expose your skin to sunlight during the midday of the day, as the sun is then giving off the most ultraviolet B.
- Where you live: people who live closer to the equator easily produce vitamin D from sunlight year around.
- Skin color: People with fair skin produce vitamin D quicker than the ones with darker skin.
Inadequate levels of vitamin D and a lack of sun exposure can cause a vitamin D deficiency and low blood levels of “calcidiol”.
The deficiency might in turn cause an impaired bone mineralization and bone damage, which can cause bone-softening disease, like rickets for children and osteomalacia for adults.
These are the symptoms of vitamin D deficiency:
- Muscle pain
- Poor Immune System
- Back Pain
- Bone Pain (and bone loss)
- Hair loss
- Muscle pain
- Slow Healing
Rickets is a childhood disease which occurs as a result of an impeded growth and soft, deformed, long bones.
This disease is caused by the lack of vitamin D, calcium, or phosphorus, but it is rare in developed countries, as milk products are high in calcium and phosphorus. As soon as the child starts walking, the bones will bend and bow under his body weight.
Osteomalacia in adults is caused by a vitamin D deficiency, and is characterized by bone fragility, softening of the bones, bowing of the legs, and muscle weakness.
It occurs in the case of 25-hydroxyvitamin D (25 OH D) levels lower than 10 ng/ml, and it elevates the risk of bone fractures, as it reduces calcium absorption and increases calcium loss.
On the other hand, the excessive intake of vitamin D supplements (i.e. 40,000 IU daily or more for at least a few months) causes vitamin D toxicity, when the liver produces too much 25 OH D levels, leading to high blood calcium levels, called hypercalcemia.
If left untreated, it leads to accumulation of calcium in the soft tissues, and other organs, like the heart and kidneys. This causes severe pain and damage.
The recommended vitamin D levels vary depending on the individual and the place he lives.
The following chart shows the average dosage of this vitamin that should be taken on a daily basis. It includes the dietary guidelines of vitamin D intake for people living in the United States, Australia, Canada, and New Zealand.
This chart illustrates the established dietary guidelines of vitamin D intake for people living in New Zealand and Australia. Did you know that a third of the people living in New Zealand and Australia have vitamin D deficiencies?
Age Group Adequate Intake (μg) Upper Level of Intake (μg)
Infants 0–12 months 5.0 25.0
Children 1–18 years 5.0 80.0
Adults 19–50 years 5.0 80.0
Adults 51–70 years 10.0 80.0
Adults > 70 years 15.0 80.0
For people living in Canada:
Age Group RDA (IU) Tolerable Upper Intake (IU)
Infants 0–6 months 400* 1,000
Infants 7–12 months 400* 1,500
Children 1–3 years 600 2,500
Children 4–8 years 600 3,000
Children and Adults 9–70 years 600 4,000
Adults > 70 years 800 4,000
Pregnancy & Lactation 600 4,000
For people living in the U.S.:
Age Group RDA (IU/day)
Infants 0–6 months 400*
Infants 6–12 months 400*
1–70 years 600 (15 μg/day)
71+ years 800 (20 μg/day)
Pregnant/Lactating 600 (15 μg/day)
These are the best natural foods that contain vitamin D:
- Potatoes: Potatoes are rich in vitamin D, and a cup of mashed potatoes with milk and butter will provide 21 IU of vitamin D.
- Corn: A cup of corn pudding will help you consume 55 IU of vitamin D.
- Spinach: It is another rich vitamin D source, and if you prepare a spinach soufflé at home, you will get 42 IU of vitamin D per measure (at one cup per measure).
- Mixed Vegetables: prepare a fresh homemade stew or soup and combine these vegetables, to optimize your vitamin D levels in the body.
Oranges are the only fruits that contain vitamin D. A cup of freshly squeezed orange juice provides 100 IU of vitamin D.
Mushrooms are high in vitamin D, so make sure you increase their intake:
- White Mushrooms: While growing, white button mushrooms are exposed to sunlight, so they are abundant in vitamin D and also help weight loss. Per serving, every ounce of white mushrooms provides 8 IU of vitamin D.
- Portobello Mushrooms: A cup of diced Portobello mushrooms satisfies 64% of the recommended daily vitamin D intake. They are also rich in antioxidants, and minerals like iron, potassium, and magnesium.A cup of diced Portobello mushrooms contains 384 IU of vitamin D.
- Shiitake Mushrooms: Shiitake mushrooms are another way to get vitamin D, as for every four shiitake mushrooms served, you get 20 IU of vitamin D.
Fish, Eggs and Meat
Cod liver oil is one of the purest sources of vitamin D, and a tablespoon provides 1,300 IU of this vitamin.
The egg yolk is another source of vitamin D, as it provides 40 IU of vitamin D.
Despite the numerous nutrients it contains, like iron, protein, and vitamin A, 3.5 pounds of beef liver will help you consume 50 IU of vitamin D.
Now, we will suggest a few delicious vitamin D recipes:
Poached Salmon with Creamy Piccata Sauce
- 1 pound center-cut salmon fillet, skinned and cut into 4 portions
- 2 teaspoons extra-virgin olive oil
- 1 cup dry white wine
- 1/4 cup reduced-fat sour cream
- 1 large shallot, minced
- 2 tablespoons lemon juice
- 4 teaspoons capers, rinsed
- 1 tablespoon chopped fresh dill
- 1/4 teaspoon salt
On a large skillet, add the salmon and half a cup of wine. Boil it over high heat, and then lower the heat, and leave it to simmer. Flip it over, cook, and cover the skillet to cook both sides for 5 minutes each.
Then, in a medium skillet, heat the oil over medium heat, and add shallot. Cook for half a minute, and add the other half of wine. Boil for a minute, add the capers and lemons, and cook for another minute. Remove it from heat, and then add the sour cream and salt.
- 2 (6-ounce) salmon fillets (about 1 inch thick)
- 1 tablespoon maple syrup
- 1 tablespoon hoisin sauce
- 1/4 teaspoon coarsely ground black pepper
- 1 teaspoon Dijon mustard
- Cooking spray
Preheat the broiler, and mix the maple syrup, Dijon mustard, black pepper, and hoisin sauce in a bowl. Stir with a whisk. Place the salmon on the broiler with the skin down, and coat the maple mixture. Broil for 12 minutes.
To sum it up, the sun exposure is the best way to optimize your vitamin D levels in the body, but there are numerous dietary sources of this vitamin available too, so make sure you always get the sufficient dosage of this “sunshine vitamin”, as a way to ensure overall health.