Vitamin D levels can affect weight loss. By increasing the amount in your blood stream, you can increase the effectiveness of a weight loss regimen.
This is something you can control. Taking a daily Vitamin D supplement can help with weight loss in addition to the things we already knew it did. It helps with bone density, immune function, inflammation and cell growth.
The RDA for Vitamin D is 600 IU/15mcg. There are questions as to whether that is high enough, so you may want to consider taking a little bit more. It is fat soluble, so, unlike Vitamin C, you can overdose on it. Institute of Medicine (IOM) has set the tolerable upper limit (UL) to 4000 IU per day for ages 9–71+ years. Make sure, if you supplement, that you are using vitamin D3 (cholecalciferol) and not the inferior form known as vitamin D2 (ergocalciferol).
If you're thinking that you already eat foods rich in Vitamin D and you're taking a supplement, you should be aware of the following things that may counter all of your really good efforts.
There are some things, besides diet that can cause low levels of Vitamin D. Certain medical problems, including Crohn's disease, cystic fibrosis and celiac disease, can affect your intestine's ability to absorb vitamin D from the food you eat. Being darker skinned or not getting enough sun exposure can limit your body's ability to naturally produce it. Being overweight may also hinder absorption of this vitamin. That's a double hurt because of it's assistance in losing those excess pounds. On top of all that are the drugs that may hurt your levels.