Obesity and Kidney Disease

The problem of obesity is well-known, but not many are aware how it affects kidneys

A Ballooning issue, obesity is derived from Latin, meaning ‘Having Eaten until Fat’. And the World Health Organisation (WHO) defines obesity as abnormal or excessive fat accumulation which may impair health. As on 2014, WHO statistics estimate that 600 million people are obese, more than one billion overweight; women are marginally more obese. What is alarming is that 41 million under the age of five are obese and between 1980 and 2014 obesity has doubled.

It is necessary to measure obesity scientifically and not to go by visual impressions. BMI, or Body Mass Index, is the standard way of measuring obesity. The formula is simple: Weight in kg divided by the square of height in meters. A number between 25 and 29.9 is considered overweight and beyond 30 obese.

This may not take into account truncal obesity, which has a better correlation to the complications. It is also called central obesity where the fat gets distributed more around the waist. This is measured by the waist-hip ratio. It should be less than 1 in men and less than 0.9 in women. The fundamental cause of obesity is the imbalance between the intake of energy-dense (high calorie) food and reduced physical activity.

Hormonal changes, psychological disturbances and drugs like steroids can also be contributing factors. Apart from complications like diabetes, hypertension, fatty liver, cancers and arthritis, which many are aware of, obesity has a unique relationship with the kidneys.

A rise in the BMI leads to an increase in the kidney function. The kidneys become larger with the enlargement of the micro filters called glomeruli. The increase in the working of the glomerulus is called hyper filtration. This leads to a drop in serum creatinine, which is a measure of kidney functioning, initially. Subsequently hyper filtration leads to leakage of proteins and closure of the glomeruli leading to kidney failure.

All forms of kidney disease worsen with obesity. The treatment of obesity basically involves reducing food portions, avoiding energy-dense foods like sugars both in the form of drinks and sweets, reducing fats, eating natural foods, and increasing physical activity.

Another disheartening fact is that weight usually does not come down with exercise alone. That is because one hour of exercise burns 200-400 calories depending on the strenuousness. But exercise has definite benefits like redistribution of fat and reducing the complications of obesity.

Drugs to lose weight are used in morbid obesity specially when diet control fails. Surgery either to reduce the stomach or bypass it is used in morbid obesity as a last resort.

Losing weight is definitely helpful in chronic kidney disease which has a prevalence rate of approximately 10 per cent of adults all over the world. In this backdrop, it was only apt that the theme of this year’s World Kidney Day should be Obesity and Kidney Disease, pushing for a healthy lifestyle for healthy kidneys.

The writer, a leading nephrologist, is Chairman and Founder of Sapiens Health Foundation, a non-profit championing the cause of kidney failure patients and preventive healthcare. www.sapiensfoundation.org/home.html

(This article was published on March 17, 2017)