Maximum Vitamin D Dosage At One Time

Vitamin D is a fat soluble nutrient that is needed for bone health, and as seen in many recent studies such as one found in the November 2010 issue of "Seminars in Arthritis and Rheumatology," vitamin D might also play a role in the prevention of many autoimmune diseases and cancers. In recent years, vitamin D has been in the spotlight due to an increase in vitamin D deficiency cases, and the dosage recommendations were even increased by the Food and Nutrition Board in 2010. However, much debate by physicians and researchers remains as to how much vitamin D a person really needs for optimal health. While vitamin D can be created naturally through sun exposure, other resources are available for supplementing your vitamin D intake and are available at various dosages.

From the Sun

Sunlight is your best and only source for natural vitamin D. When your skin is exposed to the ultraviolet rays from the sun, your body creates vitamin D. Unfortunately, the recent push for sunscreen use to avoid exposure to the sun due to skin cancer concerns has helped create the current vitamin D deficiency rise in the population. Sunscreen blocks the skin's ability to process vitamin D. Top vitamin D researcher Dr. Michael Horlick recommends that every individual receive at least 15 to 20 minutes of sun exposure three times a week. This amount should provide enough vitamin D to maintain normal blood levels. Depending on the strength and time of day you spend out in the sun, your body is able to produce as much as 20,000 IU of vitamin D. Because this is the way bodies were intended to make vitamin D, the body also does not allow too much vitamin D to be produced and will metabolize any natural vitamin D created in excess, eliminating the possibility of vitamin D toxicity.

From Food Intake

Unlike most vitamins your body needs, vitamin D is not found naturally in many foods. Due to rickets outbreaks in children in the 1930s, milk fortification with vitamin D began. However, an 8 oz. glass of fortified whole milk only provides 100 IU of vitamin D. Salmon is the best source of dietary vitamin D, but how much you receive will depend on the type of salmon you are eating. Fresh, wild salmon is your best choice, as it provides 600 to 1,000 IU for a 3.5 oz. serving, compared with farm-raised salmon, which only provides 100 to 250 IU. Certain foods, such as cereals, are also fortified with vitamin D, but the amount is usually minimal. Unlike other vitamins, adequate amounts of vitamin D are not able to be acquired through diet alone, as the dosage is not enough.

Oral Supplements

The Food and Nutrition Board recommends that the average healthy adult receive 600 IU of vitamin D daily, but some researchers and physicians recommend levels closer to 2,000. Over-the-counter vitamin D supplements are usually sold in 400 IU tablets, capsules or gel tabs. The Food and Nutrition Board suggests that the maximum upper level of vitamin D taken per day not exceed 4,000 IU. For those with vitamin D deficiency, the standard prescription dosage is 50,000 IU tablets once a month, or in severe cases can even be given once a day for a few months until blood levels are within the optimal range.

Injectable Supplements

Injectable vitamin D supplements are used in some severe cases of vitamin D deficiency and can be given in amounts of 600,000 IU once a month until your blood level reaches an optimal range. Injectable supplements have also become a treatment for dialysis patients and according to a study published in "Oxford Journals" in July 2008, the injectable dose is 20,000 IU.

Factors Affecting Dose

When it comes to a recommended maximum dose for vitamin D supplementation, many outside factors need to be considered. A physician must look at your diet, your average sun exposure, your current vitamin D blood level and your weight. Because vitamin D is fat soluble, obese patients tend to store vitamin D in fat deposits, which leave it unavailable for the body to use when it is needed. Because of this, and the other factors mentioned, a standard maximum dose might need to be increased.