Kidney Disease and Sugar

Chapter summary

Chronic kidney disease (CKD) is an epidemic, affecting about 13% of the population.
One in seven hospital admissions is due to CKD, mostly dialysis.
You can lose 95% of kidney function before symptoms appear. Treatment must then be prompt or death follows.
The author says sugar is a major contributor.

One in ten deaths were CKD related.
Three times as many people were treated as in 1991.
One in two treated cases needs dialysis.
Indigenous Australians are treated six times as often as non-indigenous Australians.
One in three Australians has high blood pressure, which causes about 30% of CKD.
One in 25 has diagnosed diabetes, which causes about 35% of CKD.

Diabetes: high blood sugar damages the kidney’s small blood vessels.
High blood pressure: it also rises because of CKD, causing further damage.
A narrowed renal artery, and long-term use of some medicines such as NSAIDs (ibuprofen and celecoxib).
Measurement: The glomerular filtration rate (GFR) is normally 60 to 90 ml/min per 1.73 m². CKD ranges from 15 to 60. Below 15 is kidney failure.
The Framingham group (over 22,000 people) found CKD is itself a risk factor for cardiovascular disease.

Human trial: You cannot ethically feed people a diet that may give them kidney disease. Brymora and colleagues took 28 CKD patients and cut fructose from 60g to 12g a day for six weeks, then back again. Low fructose reduced inflammation, with possible benefit for blood pressure. It was small and short.
Rat trial: Gersch (University of Florida) fed rats 60% fructose, 60% glucose or standard chow for 17 weeks. The fructose group had larger kidneys, glomerular scarring, tubular damage and higher inflammatory markers (MCP-1).

“Moderation” supporters: A diet of 60% fructose is far beyond normal intake, so the rat results do not apply.
The author: The author recalls his son at 16, living on Coca-Cola and white bread, and wonders if his intake was that high. His concerns are threefold: (1) CKD seems partly independent of blood pressure and diabetes, (2) damage in animals appears within six weeks, so what will 6 or 60 years do, and (3) is there a safe level, given damage can be irreversible?
Caution: Evidence in humans is limited. See your doctor if you have kidney problems.

The only remedies for kidney failure are dialysis or a scarce transplant, so prevention matters.
Take out fructose and keep consumption very low. One apple has about 14g of fructose.
Control blood pressure and blood sugar.

Australian Institute of Health and Welfare (2013) Chronic kidney disease in Australia.
Weiner, D. et al. (2005) Chronic kidney disease as a risk factor for cardiovascular disease and all-cause mortality: a pooled analysis of community-based studies. J Am Soc Nephrol.
Gersch, M. et al. (2007) Fructose, but not dextrose, accelerates the progression of chronic kidney disease. Am J Physiol Renal Physiol 293:F1256-61.
Brymora, A. et al. (2012) Low-fructose diet lowers blood pressure and inflammation in patients with chronic kidney disease. Nephrol Dial Transplant 27:608-12.