The numbness in your arms and legs is probably due to hypothyroidism. Cramps or numbness is one of the symptoms of this condition, and high cholesterol is another complication, which is probably why you are suffering from both conditions. Treatment of the underlying condition should take care of the numbness as well, so you should continue with whatever treatment you are taking for hypothyroidism. In case you are not on treatment, you should visit your doctor and begin treatment immediately - the only way to handle hypothyroidism is to take thyroid supplements to make up for the lack of natural production of the hormone by the body. Meanwhile, some general measures to reduce the discomfort include stretching and massaging your arms and legs. You should however also mention the numbness to your doctor on your next visit, as it might be due to some other problem.
One thing however - it is not clear exactly why you are taking niacin. If it has been prescribed by your doctor, you should certainly continue to take it, but if not, ask your doctor about it before continuing. It is great that you are taking fish oil however, as it is an excellent source of omega 3 fatty acids, which are considered to have a number of health benefits, including regulation of cholesterol and blood pressure, prevention of heart disease, and improvement of blood circulation.
answered by M W