Brain tumor research is a relatively modern science that parallels the explosion of molecular biology and modern neuroimaging. While the science is new, Mayo Clinic has a long history of brain cancer treatment and research stretching back over 100 years.
But not all vitamins are water-soluble, and the ones that are lipid-soluble, meaning they like to hang around in your body's fat, don't get flushed out. Instead, if you take too much of a lipid-soluble vitamin over a few weeks to a month, they sit in the liver and can build up to toxic levels, causing problems ranging from weak bones to liver damage, according to Katherine Zeratsky, a registered dietician nutritionist at the Mayo Clinic.
Excess Fat-Soluble Vitamins. Your body stores fat-soluble vitamins, and excessive amounts can accumulate at toxic levels and damage your organs. The only fat-soluble nutrient for which the IOM has not set a UL is vitamin K. Taking too much vitamin A can cause dizziness, nausea, headache, bone or joint pain, and can be fatal.