Do you have problem with kidney or are you worry about it? Let’s learn about it and supplements should avoid.

Sign and Symptoms

There are no typical signs and symptoms in the early stage of kidney damage. Most kidney diseases are found accidentally in medical check-ups. If you already have specific symptoms, your kidney has been in the process of deterioration for a long time. It is very important to detect kidney damage in the early stages, so go to the hospital regularly if you are worried about it. 

It is not easy to take regular medical check-ups; remember, you should not ignore severe signs or symptoms. Depending on how severe it is, many can caused by kidney malfunction.(1)

1. Gastrointestinal disorders: like nausea/vomiting, loss of appetite
2. Fatigue and dizziness: Fatigue and weakness, Not easy to concentrate (Decrease mental sharpness), and insomnia
3. Unusual welling: especially feet and ankles
4. Urination: urinate more or less, weight loss
5. Systemic order: high blood pressure, chest pain around the heart

Signs and symptoms of kidney disease are often nonspecific. 

Supplements you should avoid

1. Heavy metal-containing nutrition products: Excessive amounts of heavy metals are harmful to kidney functions. Most products stay under good quality control, but not all of them. Not adequately checked by the FDA or reliable institutions, Many supplements might contain heavy metals over permissible levels. Heavy metals, such as lead and cadmium, are major causes of kidney malfunction. So please don’t take any kind of nutritional supplement. Check the level of heavy metals in it. 
2. Herb ingredients: If you are so in herbs, please confirm the ingredients. Extract or powder form of the herb can burden the liver and kidneys so much. Excretion through the kidney is overloaded by highly concentrated herbal supplements. And even heavy metals are frequently detected in some products. Some herbal things have aristolochic acid, which is harmful to kidneys. Find and select herb ingredients, and look at the content. Products with a single ingredient and exact dose and mark should be chosen if possible. If you have kidney failure, quit herb, and don’t take the risk of your kidney anymore. 
3. Vitamin C: High doses of vitamin C are a risk factor for kidney stone; if with history, the worse. Total and supplemental vitamin C intake was significantly associated with a higher risk for incident kidney stones(2). Take vitamin C in the proper amount; personally, under 1 g daily is enough.
4. Vitamin B: Diabetes patients with kidney disorders could be at risk of heart deterioration with high daily doses of vitamin B (folate, B6, B12). And the risk of heart attack (3). 
5. Minerals: A high dose of minerals, like magnesium, phosphorus, and calcium, have the potential to worsen the kidney.
6. Oxalates: Cranberries containing high doses of oxalate can cause kidney stones. Drinking enough water daily is important.
7. Chromium: Intake 200-400 for blood sugar control purposes. But, Occasionally, 1000-2000 mcg is damaged.

Kidney-friendly supplement
Then, what are good for the kidneys? None. There is nothing to help. Directly, there is no nutritional, herbal or functional supplement to improve kidney functions. You should consider improving blood vessels.
Ingredients beneficial to high blood pressure, diabetes, and cholesterol are helpful. Those diseases are serious causes of kidney damage, so it might be a good choice to control them.
When suffering from kidney stones, citric acid is useful since oxalate with citrate is soluble in water. Green tea or coffee, a small amount of drink, improves kidney blood flow and releases oxalate; even green tea has a small quantity of oxalate itself.

References
1) Chronic kidney disease. Myoclinic
2) Pietro Manuel Ferraro, Gary C. Curhan, Giovanni Gambaro, Eric N. Taylor. Total, Dietary, and Supplemental Vitamin C Intake and Risk of Incident Kidney Stones. PATHOGENESIS AND TREATMENT OF KIDNEY DISEASE| VOLUME 67, ISSUE 3, P400-407, MARCH 2016
3) Z. Rafeq a, J.D. Roh c d, P. Guarino f, J. Kaufman a e, J. Joseph a b d e. Adverse myocardial effects of B-vitamin therapy in subjects with chronic kidney disease and hyperhomocysteinemia. Nutrition, Metabolism and Cardiovascular Diseases Volume 23, Issue 9, September 2013, Pages 836-842