Dr. Jennifer Ashton appeared on "Good Morning America" on Wednesday, June 21 to notify viewers about a new study that indicates people are taking more Vitamin D than they need, and it might be hazardous to their health.

The sun can be the main source of vitamin D when it shines brightly in the spring and summer and people spend a lot of time outside. For most people, this is all they need.

However, there are four groups of people who need more than they might be getting. Those groups include people with dark skin, those who are obese, the elderly and those who are homebound.

Usually, younger and healthy people who get an adequate amount of sun are less likely to have low Vitamin D levels; however, sunscreen blocks it from the skin. Then supplements are needed in the correct dosage. Also, some people get enough of what they need from fatty fish like salmon, tuna, sardines, and mackerel. Vitamin D is also found in beef liver, egg yolks, cheese, soy milk, and orange juice.

Health risk

Dr. Ashton emphasized that more is not better when it comes to taking vitamin D supplements. She warned that the recent study shows that there has been a big increase of Americans taking megadoses which can increase the risk of kidney stones, fractures, and cancer.

The recommended daily intake is 600 International Units (IU) for people under 70 years old and 800 IU for people over 70. Records show that some are taking more than double the dosage. There has been an 18 percent increase in supplemental doses that had more than 1,000 IU and 3 percent of 4,000 IU. Experts are concerned over these alarmingly high rates especially since many people aren't aware of the dangers.

Benefits of vitamin D

Vitamin D helps the body use calcium to support bone health when taken in the recommended dosage. It has the opposite benefit when more is taken. Instead of bones been strengthened, they are weakened and might even be fractured.

It has been determined that 4,400 IU is the highest amount that should be consumed every day by an adult or child aged 11 to 17 without risk to their health. For children from one to ten-years-old, only 2,000 IU should be taken. Infants should not be given more than 1,000 IU per day.

The Food Standard Agency's Committee on Toxicity concluded that high intakes of the vitamin over prolonged periods have caused toxicity in humans. Many cases of poisoning from vitamin D have been reported from those who have exceeded the recommended dosage.

It is very interesting that the supplements are sold over the counter at drug stores in quantities of 5,000 IU, 10,000 IU and as high as 50,000 IU.