High ambient temperatures increase the risk of developing kidney stone disease. Kidney stones (also called renal calculi, or urolithiasis) are hard deposits made of minerals and salts that form inside the kidneys.
Kidney stones have been part of the human experience for thousands of years; a treatment for kidney stones is mentioned in an Egyptian medical text from 1500 BC.
Kidney stones are common with a prevalence ranging from 1% to 20%. A recurrence rate of up to 50% has been seen five years from the initial episode of symptomatic kidney stones. Though most kidney stones develop in the kidneys, they can form anywhere in the urinary tract. The prevalence of kidney stones is increasing worldwide, contributing to an inevitable health burden to all age groups.
Types of Kidney Stones
Kidney stones can be stratified into four types and nine subtypes based on the stone composition and etiology, including non–infection stones (calcium oxalate, calcium phosphate, uric acid), infection stones (magnesium ammonium phosphate, carbonate apatite, ammonium urate), genetic causes, and drug stones.
Does Climate Change Cause Kidney Stones?
People living in hotter climes are likely to sweat more, so it follows that they are also more likely to be dehydrated. And being chronically dehydrated is a well-established risk factor for kidney stones.
A warming planet will likely cause an increased burden of kidney stone disease on health care systems. Heat, humidity, and lack of proper hydration all lead to a higher prevalence of kidney stones in the summer. The main reason is due to the amount of water we take in and use.
In the heat of summer, as people are outdoors exercising, they lose fluids through perspiration. It takes about 90 minutes to form a kidney stone. Usually, the fluid in urine prevents waste products from coming into contact with each other. However, kidney stones can begin to form when there is not enough fluid or too much solid waste content in the urine.
Kidney stones often have no definite, single cause, although several factors may increase your risk.
Kidney stones form when your urine contains more crystal-forming substances — such as calcium, oxalate and uric acid — than the fluid in your urine can dilute. At the same time, your urine may lack substances that prevent crystals from sticking together, creating an ideal environment for kidney stones to form.
Family or personal history. If someone in your family has had kidney stones, you're more likely to develop stones, too. If you've already had one or more kidney stones, you're at increased risk of developing another.
Dehydration. Not drinking enough water each day can increase your and those who sweat a lot may be at higher risk than others.
Certain diets. Eating a diet that's high in protein, and sodium (salt) may increase your risk of some types of kidney stones. Too much salt in your diet increases the amount of calcium your kidneys must filter and significantly increases your risk of kidney stones.
Obesity. High body mass index , large waist size, and weight gain have been linked to an increased risk of kidney stones.
Digestive diseases and surgery. Gastric bypass surgery, inflammatory bowel disease or chronic diarrhea can cause changes in the digestive process that affect your absorption of calcium and water, increasing the amounts of stone-forming substances in your urine.
Other medical conditions such as renal tubular acidosis, cystinuria, hyperparathyroidism and repeated urinary tract infections also can increase your risk of kidney stones.
Certain supplements and medications, such as vitamin C, dietary supplements, laxatives (when used excessively), calcium-based antacids, and certain medications used to treat migraines or depression, can increase your risk of kidney stones.
Small kidney stones may not cause any symptoms, and they sometimes pass on their own without causing much discomfort. Medium-to-large kidney stones, however, can cause intense, sharp pain.
Common symptoms of kidney stones include constant, intense pain in the lower back, bloody urine, vomiting or nausea, often from the pain, fever, and chills, very unpleasant or odd-smelling urine, cloudy urine, and stomachache that does not improve with gas medication.
Added Sugar Increases the Risk of Kidney Stones
New research shows that added sugar consumption may be a risk factor for developing kidney stones. Some studies have linked sweetened drinks containing high-fructose corn syrup, to the development of kidney stones.
The negative health effects of added sugar, such as high blood pressure, insulin resistance, and obesity, are also risk factors for kidney stone formation. Added sugars can also lead to less urine volume and elevated urinary calcium, which may lead to the development of kidney stones.
Complications of kidney stones include acute renal failure secondary to obstruction, anuria, urinary tract infection with renal obstruction, and sepsis.
Stay hydrated. Drink between six and eight glasses of water per day.
Reduce salt intake. Sodium, or salt, can cause water retention and lead to dehydration.
Maintain a healthy body weight. Being overweight or obese can put stress on the kidneys. However, it is always important to lose weight gradually and safely. Crash dieting and following a diet high in animal protein can both increase the risk of kidney stones.
Limit foods with calcium oxalate. Kidney stones can consist of many different compounds, including uric acid, struvite, and cysteine. The most common type of kidney stone involves calcium oxalate. Foods that contain high levels of oxalate include grapefruit and cranberry juice, potatoes, soybeans, spinach, some nuts, including cashews and peanuts, chocolate, beets, asparagus, most berries, celery and parsley, whole grains, and tea.
Avoid excessive caffeine consumption. Caffeine speeds can cause dehydration. Remember that certain sodas, chocolate, teas, and energy drinks can also contain caffeine. Avoid sugary drinks.
Getting enough dietary calcium. Although calcium oxalate is the most common compound in kidney stones, consuming some dietary calcium helps reduce the risk of stones. Most dairy products are a good source of calcium.
Increase citric acidic intake. About 60% of people with kidney stones also have low citric acid levels. Some good sources of citric acid include undiluted, unsweetened lemon juice, orange juice, melon juice, or mango juice.
Monitor the intake of high acid foods. Highly acidic urine can increase the risk of uric acid kidney stones and make passing them more painful. High amounts of acid in the urine also encourage the kidneys to reabsorb citrate rather than excrete it. Citrate is a compound that can help flush out calcium-based stones, as well as impair their growth. Highly acidic foods include red meat, poultry, most types of fish, most cheeses, and eggs.
A person should monitor and limit his intake of these foods if he experiences frequent kidney stones.
Exercise Improves Circulation, and Filtration
Regular moderate exercise increases blood flow to the kidneys, which in turn improves their filtering abilities. In addition, consistent workouts help in maintaining the levels of salt, calcium, and minerals in the body. Excess calcium in particular gets diverted to the bones, thereby preventing it from combining with the oxalate to form calcium oxalate, the major reduce the chances of such minerals sticking to the stone while potentially keeping the size of the stone in check.
Engaging in any type of light physical activity can reduce the risk of kidney stones by 31%. Even light gardening or housework might attenuate the development of the problem. Interestingly, no particular mode of exercise provides an advantage in preventing kidney stone formation; the amount of movement, not the intensity, makes the difference.