Kidneys are incapable of filtering. The kidneys' function is to filter blood. This filtering process involves controlling how much water is retained in the bloodstream and how much is excreted as urine. Too much salt may impair the kidneys' ability to adequately remove fluid waste, leading the body to retain extra water. This can cause weight gain, increased heart rate, and increased pressure inside the skull referred to as "high blood pressure". Urinating more often than usual is also a sign of high sodium levels in the body. The only way to prevent people from eating too much salt is with food labeling laws. If a product has 5 grams or less of salt per serving, they must label it as such. If a product has 6-7 grams of salt per serving, it does not have to be labeled. There is currently no federal law that requires manufacturers to label foods with respect to their salt content. Some states like California and Maine have passed legislation requiring salt labels on packaged foods, but these laws are not uniform nationwide. Here are some tips for reducing your intake of salt: Read the labels. Look for products that are low in salt. You can usually reduce the amount of salt in recipes by choosing lower-sodium alternatives such as 7UP or spring water instead of regular soda, and cooking with herbs and spices rather than salt. Get advice from your doctor.