is a common problem, especially in the summer months
and has been considered temporary and easily treatable. An increase in the
in Central America's sugarcane workers exposed to heat-induced dehydration
raised concerns regarding the long-term
effects of dehydration on kidney health. This led to a study by Richard J.
Johnson and his team which revealed that dehydration caused due to exposure to
heat resulted in chronic kidney damage in wild-type mice.
‘Soft drinks may not be the best way to rehydrate yourself as they may worsen heat-induced dehydration and kidney injury.’
The recent study by Garcia-Arroyo and team has gone a step further and
tried to investigate the effect of the type of drink used for rehydration
immediately after exposure to heat on the degree of kidney injury. The team
comprises of researchers who are
inventors on patent applications of drugs to prevent kidney damage by
metabolism. They are funded by Amway and
Rats were divided into three groups and exposed to heat stress. The
first group was offered plain water, the second was given water containing
fructose and sucrose in concentrations (11%) similar to that found in soft
drinks, and the third was offered water containing stevia
(non-caloric sweetener) for two hours
following heat exposure. All the groups were given plain water for the rest of
the day. This study was conducted over a period of 4 weeks. An increased
oxidative stress and renal inflammation were observed in all groups except the one fed on plain water. This
confirmed the association of dehydration with renal injury.
Moreover, the degree of renal injury was the maximum in the group that
was fed on the fructose-sucrose
The study raises concern on two main issues:
The association of dehydration with chronic
There are so many reasons due to which most people are exposed to
varying degrees of mild to moderate dehydration like drinking less water due to
busy schedules, incontinence issues, and poor habits. If the study is accurate,
it means that even mild yet recurrent episodes of dehydration may expose
individuals to an increased risk of CKD. Three effects of dehydration may be
responsible for the same:
secretion of vasopressin (a hormone
that promotes water retention and an increase in blood pressure).
- Activation of the aldose-reductase-fructokinase
- Chronic hyperuricemia (increased uric acid in the blood).
Carbonated drinks like soft drinks may be
harmful to kidney health
There was an increase in intake of water observed in the groups fed on
fructose-sucrose water as well as the stevia-containing solution. Despite the increased intake, there was
increased kidney damage in the former group.
The concentration of sugars was similar to that in soft drinks. Though
soft drinks have not been tested per se, this study warrants further
investigation to determine the correlation.
The authors of the study said, "Our studies raise serious concerns for the common practice, especially among adolescents and young adults,
to drink soft drinks as a means to quench thirst following an episode of
Another interesting observation was the reduction of kidney injury and
arterial pressure in the stevia-fed group. A possible theory is the action of
stevia as an osmotic diuretic to negate the effects of hypertension induced by
dehydration and the resulting kidney injury but it needs to be investigated
further for confirmation.
A literature review conducted in the year 2014 analyzed the association
of sugar-sweetened soda and chronic kidney disease. Studies that reported odd
ratios comparing CKD incidence in patients who consumed sugar-sweetened sodas
in significant quantities as compared to those who consumed artificially
sweetened sodas were included, a total of five in number. Pooled risk ratios
(RR) were calculated. The pooled RR of the group that consumed sugar-sweetened
sodas was found to be 1.58 while that of the group which consumed artificially
sweetened sodas was 1.33. Thus, the review and meta-analysis of the five
studies revealed a statistically significant difference in risk between the two groups in relation to CKD.
The rat study by Garcia-Arroyo reaffirms the association of
sugar-containing drinks and kidney injury, albeit in rats.
This makes it pertinent to not only avoid dehydration due to heat in
summers as it may cause kidney damage but also choose water over any other
drink to rehydrate the body after any exposure to heat stress.
- You Are
What You Drink! Editorial Commentary: Rehydration with Soft Drink-like
Beverages Exacerbates Dehydration and Worsens Dehydration-associated Renal
acclimation and thirst in rats