For vitamin-insufficient population, food options are wide for vitamin D

Vitamin D fanatics may spend hours at the beach catching tans to increase their levels, but there are also nutrient-rich foods packed with the key vitamin and available at a store near you.

Fish
According to Men's Health, only 3 ounces of wild salmon can provide 112 percent of your daily value of the vitamin. Not only is wild salmon delicious – it's also high in omega-3s, which are polyunsaturated fatty acids known for their potential to improve metabolism. According to the FDA, one three to six ounce canned salmon serving can provide as much as a week's worth of omega-3s.

People have been pairing salmon with bagels and cream cheese for years, but more varied options also exist, such as mixing it with avocado to get more heart-healthy fats, or adding lemon juice or capers for taste. If you're in a hurry, salmon even goes well with toast.

But salmon isn't the only chicken of the sea with vitamin D and omega-3s. Tuna, in addition to being a good source of protein, also has a healthy amount of vitamin D. This fish goes well with pickles, lettuce and mayonnaise. Just avoid buying tuna that comes packaged in a can. While canned salmon has mercury levels below FDA detection, canned tuna has at least 35 times more mercury, according to the ocean conservancy group Oceana.

Tuna with healthy mercury levels will be labeled as "chunk tuna" or darker meat tuna, provided by a different species than the "white" or "chunk light" tuna often found in cans. The darker tuna is smaller, and smaller fish take in less mercury.

Fruit & Dairy
Orange juice is also well-known for its richness of vitamin D, with one cup providing about one third the average daily value. Fortified Milk also includes the vitamin in moderate amounts, and you're likely to find vitamin D enriched milk in supermarkets. Other dairy products like yogurt also contain vitamin D. Yogurt is also a great snack for post-workout, when your muscles need protein for repair.

Vitamin D performs a number of key functions in the body, primarily in the absorption of calcium and phosphorus, which have been shown to boost bone health. In the body, the active form of the vitamin is called Calcitriol, and it has been linked to increased calcium absorption in the kidneys as well as greater percentages of the mineral in the bloodstream.

Population deficiencies
Data from the 2009 National Health and Nutrition Examination Survey showed that nine percent of children in the United States are deficient in vitamin D (lower than 15 ng/mL in blood), with 61 percent vitamin D insufficient (15 to 29 ng/mL). While vitamin D is generated through sun exposure, the evidence is clear that many may not be getting enough sunlight to get optimal levels of the key compound. Increasing vitamin D intake through food may be a good way to supplement diet regardless of sunshine exposure.

Vitamin C
Another vitamin easily available in foods is vitamin C, for which the most famous example is perhaps oranges. Vitamin C may raise immune system health and has been linked to higher levels of iron absorption.

Other foods high in the vitamin include guava fruit, kiwis, red and green sweet peppers, grapefruit, strawberries, cantaloupe and brussel sprouts. Strawberries are also high in fiber and antioxidants, and a red pepper can boast more than 100 mg of vitamin C, according to numerous studies.

Next time you go out to eat, you might want to try some lox with a side of orange juice, or there may be some yogurt or kiwis lying around to mix into a vitamin-rich snack for work. In the end, sunlight may be good for you, but it's not the only way to get your fix of vitamins.