Protein drinks are typically made from rice, whey, egg, soy or a combination of these ingredients. Many manufacturers recommend that you use their product multiple times during the day. However, in some cases, this may mean you are consuming more than the safe intake level for cadmium or other heavy metals like lead or arsenic.CadmiumCadmium is a soft metal that occurs naturally in the ground. It is a heavy metal, like lead, and is toxic when inhaled or consumed.Cadmium interferes with the filtering systems of the kidney, causing abnormal amounts of amino acids and glucose to be excreted in the urine, interfering with the way your body absorbs protein and causing chronic toxicity of the kidney when consumed in excess. It builds up in your kidneys, bones and lungs.It can take 20 years to eliminate just half of the cadmium you consume in a day, notes Consumer Reports. Many people who use protein powders also consume excess amounts of protein, which further adds to the stress put on the kidneys.Cadmium in riceWhen rice is grown in soil that contains high cadmium levels, this heavy metal gets absorbed into the rice while it is growing. Cadmium can get into the soil from industrial waste, but it is also common in certain types of fertilizers that are applied to soils routinely for growing crops.Rice is one of the seven foods that, together, account for approximately 65 percent of cadmium intake through food, according to the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives.Cadmium in protein powderRice protein powders are made from one of the foods most likely to be contaminated with cadmium, so they may contain this heavy metal in at least small amounts. Many people who use protein powders consume three or more servings per day.Consuming this amount may cause you to consume more than the recommended limit of 5 micrograms per day set by U.S. Pharmacopeia, according to research published in July 2010 in "Consumer Reports."Consumer Reports tested 15 different protein powders, not all of which contain rice. Although different samples yielded different results, for each drink tested, there was at least one sample that contained cadmium, mercury, lead or arsenic.ConsiderationsRice protein powders are more risky if they contain multiple heavy metals, as these often harm the same parts of the body and have a cumulative effect.Children, pregnant women and young adults should be especially careful about consuming products that may contain cadmium. Most people get plenty of protein in their diets without consuming protein powder.It is best to increase your protein intake through the consumption of protein-rich foods rather than consuming a product that may contain contaminants like cadmium, recommends Consumer Reports.