Kidney stones are extremely painful stones that are caused by an inability of the body to excrete waste products effectively due to issues with kidney function or an excess accumulation. They are more common in western societies, due to the influence of the diet, and have a high reoccurrence rate of 35-50% over 5 years.
Who Should You Be Monitoring?
Anyone can develop kidney stones, but particular attention to these groups below.
- Elderly – risk increases with age
- Western world populations
- Individuals with anatomical kidney abnormalities
- Males – 3:2 ratio compared to females
- Previous history or family history of kidney stones
- Geographical location – hot, humid environments can impair hydration status
- Obesity (men and women have 33% and 200% increased risk respectively)
- Individuals after Bariatric surgery – risk of excess urinary excretion of oxalate
- Metabolic conditions – i.e. diabetes, gout, hyperparathyroidism
How Do We Help?
Prevent Weight Gain – All High-Risk Categories
At higher weights, reductions in renal ammonium production can occur which can lead to low urinary pH levels which consequently increase the risk of uric acid and calcium oxalate stone development.
Just Drink Water
A comparison of fluid intake of 1.5L compared to 2L per day showed that the latter reduced risk of first kidney stones by 8%. This risk is further reduced by 26% as fluid intakes increase to 3.1L.
Don’t Avoid Calcium
Dispel the misconceptions around actively avoiding or reducing their calcium as diets meeting 50-100% of requirements actually reduces oxalate absorption, and in turn stone formation risk.
Reduce Animal Protein
This can lead to a reduction of urinary calcium oxalate and urate. As such, a vegetarian diet holds potential as a management strategy that could be encouraged on a case-by-case basis with your clients.
Cut the SSB’s
Remove those sugar-sweetened beverages as these have an associated 23% increased risk. This is likely related to the high fructose corn syrup which increases the excretion of calcium, oxalate and uric acid in the urine. Caffeine has an inverse relationship with stone development risk suggested by the potential increase in urinary excretion and subsequent lowering of oxalate. The more peeing the better.
Citrate May Help
Citrates found in foods such as oranges, berries, lemons and limes could be included in the daily diet. Supplementation of citrate (as a dose of 6-10g/day of potassium citrate) is a common prescription for those who have suffered from kidney stones.
Up the Fruit and Veggie
High intakes >500g per day (of low oxalate content) can excrete more citrate in urine which discourages stone formations.
Conclusion
Now you can see the impact of diet on kidney stones, the next time you are reviewing clients with any of the above risk factors, you should be considering these nutrition interventions.
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