Seasonal Changes and Vitamin D Levels
When seasons change, our bodies change too. A study in Time magazine found that vitamin D levels drop a lot in winter. About 63% of adults don't get enough vitamin D in winter, but only 6% in summer.
This drop is more in places with less sunlight. Our bodies make vitamin D when skin meets sunlight. But in winter, we get less sunlight, so we make less vitamin D.
This makes us wonder how to keep our vitamin D levels up. We might eat more fatty fish and mushrooms. Or look for other ways to get it.
1. The importance of vitamin D :
Vitamin D is more than just a vitamin. It's a hormone that helps our bodies use minerals. It helps our bones stay strong by making them absorb calcium and phosphorus.
Vitamin D also helps our immune system. It helps fight off infections and keeps our immune system from getting too strong. It also helps our muscles work better and keeps our bones healthy.
Keeping vitamin D levels right is key for staying healthy. Adults need at least 600 IU of vitamin D every day. Older adults need more because their bodies make less.
Children need about 400 IU of vitamin D to grow strong bones. It's important to get the right amount of vitamin D. Too little or too much can be bad for our health.
2. Biological Mechanism for Obtaining Vitamin D :
The body gets vitamin D through two main ways. The first way is when the skin makes it from sunlight. This happens when UVB rays hit the skin, turning 7-dehydrocholesterol into previtamin D3, then into vitamin D3.
The amount of vitamin D made this way depends on the sun's angle, skin color, and how much skin is exposed. This is why people in colder places make less vitamin D in winter.
The second way is through food. Vitamin D is found in some foods with a lot of fat. Foods like salmon, mackerel, cod liver oil, and egg yolks are good sources. Some mushrooms and fortified foods like milk also have vitamin D.
Vitamin D from sunlight or food is not active at first. It needs two changes to become active. The first change happens in the liver, making it 25-hydroxyvitamin D. The second change happens in the kidneys, making it calcitriol, or 1,25(OH)2D.
This active form of vitamin D is what the body uses. If we don't get enough from the sun or food, we might need supplements.