Although Vitamin E is a fat soluble vitamin, it has a fantastic safety record. Clinical trials of vitamin supplementation as high as 3200 IU per day have not shown any adverse effects. In addition studies have shown that vitamin E inhibits platelet aggregation and decreases the risk of blood clots in much the same way asprin does. This property of vitamin E is actually a benefit in reducing heart disease. Researchers believe that vitamin E actually improves the effectiveness of asprin on patients with heart disease.
Vitamin C is safe even at very high doses, although some people may experience abdominal bloating, gas or diarrhea. At one point, there was concern that vitamin C supplementation might increase the risk of kidney stones. This was found in only one clinical trial; however the last four similar trials did not substantiate this concern.
Vitamin D great potential to cause toxicity. Dosages greater than 1500 IU are not recommended. In most cases I do not recommend supplementing with vitamin D in doses greater than 800 IU per day. Vitamin D toxicity may increase the blood levels of calcium, cause deposits of calcium in internal organs and increase the risk of kidney stones.