Vitamin D3 is good for your heart and brain. It regulates your insulin sensitivity, promotes the body's production of antibiotics, and helps with the absorption of the amino acid leucine. The latter is especially important for protein biosynthesis and thus for muscle building.
Unlike many other vitamins, your body can synthesize vitamin D3 itself. However, the prerequisite for this is the contact of your skin with UV radiation through sunlight. In summer, your body's own vitamin D3 content is therefore probably significantly higher than in winter. However, this is only the case if you are often outside in light clothing and use little or no sunscreen.
On gray winter days, your body hardly produces this vital vitamin at all. Among other things, this has a negative effect on your mood and wellbeing. Therefore, it makes sense, especially in winter, to consume vitamin D3 through dietary supplements. This helps, among other things, to brighten your mood especially in winter.
Vitamin D3 is a fat-soluble vitamin, which is why you should consume it in combination with fat. It has numerous health benefits. Healthy bones and teeth, for example, are the result of an adequate intake of vitamin D3, but your hormone function and your immune system can also see improvement.
If you want to find out whether or not you should supplement vitamin D3, you can have a blood test done by your doctor. But even without blood work, it makes sense to take the vitamin.
Vitamin D3 is also found in very small amounts in foods such as fish, eggs, beef, nuts, cheese, and cod liver oil.
Most people (over 2/3 of the western population) have a vitamin D3 deficiency. Therefore, it is advisable for most people to supplement vitamin D3. The recommended daily dose is 400-800 IU per day. This may still be too little for most adults. With a daily dosage of 1,000-2,000 IU of vitamin D3, you are on the safe side. However, there is also evidence that higher dosages of 10-40 IU per lb provide even more benefits.
When taking vitamin D3, you should generally make sure to consume it with vitamin K2. Otherwise, in the worst case, it can lead to osteoporosis, a bone disease in which bone density decreases over time.