Our newsfeeds are always full of the latest health and diet trends; eat this, don’t eat that, take this, don’t take that – you know what we’re talking about. But there’s one vitamin who’s shine never seems to dull and that’s vitamin D. So what role does vitamin D play in your quest for an active and healthy lifestyle? A pretty damn important one.
As nutrients go, vitamin D is a rarity: It’s one of only two vitamins your body makes on its own. The liver, kidneys and cells and several other parts of the body convert two forms of vitamin D to its active form, the steroid hormone 1,25-dihydroxyvitamin D, and any extra is stored in fat tissue for future use. Vitamin D2 is found in plant sources and can enter the body only through what you eat. The more potent vitamin D3, which can be produced through sun exposure, from animal products or supplementation, tends to be more readily converted to the active form in the body.
In theory, we can make all the vitamin D we need; in reality, we don’t. In fact, slathering on sunscreen with an SPF of 8 or higher blocks the ultraviolet B rays that generate vitamin D production. In addition, relatively few foods provide vitamin D – that’s not to say you shouldn’t be wearing sunscreen! But a lower SPF and time outdoors, out of direct sunlight, outside the hours of 12 – 3pm will do you good.
Vitamin D Improves Immunity
Colds, flu and other respiratory problems are more common during the months when we’re outside the least – in the West this is often during the winter, but here in the UAE the summer heat has us hiding inside, bathing in our AC and rarely seeing the sun unless we absolutely have to. Vitmain D plays a vital role in revving up the immune system by boosting the activity of cells that battle bacteria and viruses all year long.
Vitamin D Helps You Build Stronger Bones
There’s a reason why milk has added vitamin D: Calcium needs it to build strong bones and help you avoid osteoporosis down the road. Without vitamin D, calcium would be nearly useless since it regulates calcium’s absorption from food and supplements and directs its movement in and out of bones.
Low levels of vitamin D also play a role in osteomalacia, the adult version of rickets, a condition characterized by unrelenting bone pain, muscle aches and muscle weakness. Osteomalacia makes it difficult to work out and, as a result, may lead to weight gain and loss of muscle tissue. Overweight people are particularly prone to the condition, because excess fat absorbs vitamin D and makes it unavailable to nurture bones and muscle.
Vitamin D is a Muscle Builder
Considering that vitamin D actually gets converted in the body to a steroid hormone, it makes sense that it would affect muscle tissue. The active form of vitamin D binds to specific receptors found on muscle cell membranes and in muscle cell nuclei. When it binds to these receptors, it enhances muscle contraction and protein synthesis, which is the buildup of muscle protein.
Research shows that certain types of these receptors may be responsible for greater muscle size and strength. Although you can’t alter the type of vitamin D receptors you have in your muscles, making sure you have adequate levels of vitamin D in your body can help ensure that your muscle vitamin D receptors are activated for optimal muscle function, strength, and growth.
So how much vitamin D do you need?
Vitamin D supplementation involves very little risk so taking in more than the recommended daily allowance (200 IU per day) is probably a good idea. Experts recommend consuming 1,000 IU daily as cholecalciferol (vitamin D3), the most beneficial form. People with naturally darker skin should consider taking vitamin D supplements, because melanin acts as a natural sunscreen, limiting their bodies’ ability to produce it.
As with most supplements, you can get too much of a good thing, so limit your intake to 2,000 IU per day. And while research points to supplementation as one of the best ways to get enough D, don’t use that as an excuse not to eat a balanced diet.