Eating Sugar? Beware of Kidney Disease

That sweet tooth could be hurting your kidneys, and not just your heart!


Most people, even the ones outside of medicine, will tell you that we are getting heavier with time. Our average blood pressures today also tend to run higher than what they did a hundred years ago. We have more diabetes and we have more heart disease. 

It wasn't always like this. Not till the very recent past. And I am talking about as recently as the early 1900s! What happened to you America? Could our changing diets hold a clue?

If so, what specifically might be the culprit?


The idea that our diets have changed more drastically in the last century than ever before (over a hundred year period of time) is now a scientifically accepted fact. Parallel to this change has been the rising incidence of chronic diseases. Today, one-third of adults in the US are obese. One-third of adults in the US have hypertension. A little under 10% have diabetes.

Sugar may be a big part of the answer to the above question (if not the complete answer- other culprits include processed foods and oils, more caloric consumption, lifestyle changes, etc). In huge amounts. Cheap and omnipresent. To understand the effects of sugar consumption on health and kidney disease, let's take an interesting detour into the history of sugar consumption. Once one understands  how sugar's (over)use has grown in parallel with the increasing incidences of heart and kidney disease, diabetes, etc since the eighteenth century, the link between sugar consumption and adverse health consequences becomes clearer.


When Dr Symonds published his findings about high blood pressure in New Yorkers of the early 1900s, he found that barely 5% of the population had a blood pressure over 140/90. However, things later started to change. Yes, we began to eat more; but we also started to eat differently.

And as affluence and abundance grew in post-war America, so did sugar consumption. Average US annual per capita sugar consumption that stood at well under 100 pounds when Dr Symonds published his findings had increased to over 150 pounds towards the latter half of the century. And more sugar meant more condensed calories. Calories that made us heavier.

One doesn't necessarily need a randomized trial to prove that we have grown fatter over the decades. Data drawn from US Civil War veterans' health surveys shows that in 1890, the prevalence of obesity was around 3.4%. This increased to 35% by the year 2000. Closely following this increased prevalence of obesity (and hypertension, and diabetes), the prevalence of end stage kidney disease went up 4-fold between 1980 and 2002.

However, the fact that we developed a sweet tooth over the last century does not necessarily prove that that is in fact the cause of increasing incidences of hypertension, diabetes, kidney disease etc. But it does make us wonder if our changing dietary habits, specifically the increasing consumption of sugar might have something to do with it.

And here is why I think that sugar might be a big part of the puzzle...


Sugar has been around in the Indian subcontinent for at least 3000 years. However its trade really started once the Indians figured out a way to turn sugarcane juice into sugar crystals. Later, Alexander the Great's army would note the Indians using a "sweet salt" that they called "Sarkara". This became the root word for sugar, saccharum, and saccharin. Later traders would take the Silk Road to the Orient to procure it (see their route on the accompanying picture). The subcontinent would remain the major center of sugar export to the world until sugar production started in Venice in the 15th century (see the timeline here). However, even then sugar was a niche product to be bought only be the wealthy one-percent-ers! The royal families of Europe would gift it to each other. Over the next century though sugar would change the political and health landscape of humanity forever. The health consequences are obvious. The political upheavals I am referring to is the advent of colonialism and slavery.

For a good part of my life, I worked on the Caribbean island of Grenada. A favorite pastime was hiking trips to what used to be a sugar plantation (they also make a killer dark chocolate!) from the 17th century to the early 1900s. The trips were my first tangible view into the history of sugar trade. Looking over that estate, I would picture the enslaved Africans who were made to toil in inhuman conditions while they churned sugarcane juice into white sugar crystals. Crystals that were then sent up to England and France to satisfy the palates of the colonial masters.  Thanks in part to the evolving tastes of Europeans, and in part to its rarity, sugar quickly became the most important and lucrative commodity in world trade. Its importance was no less than what oil's is today!

Why am I discussing history on a health blog?! Well, I would ask you to re-read the statistics I wrote above. The reason you see these overwhelming numbers is related to the easy availability of sugar. As sugar became easier to produce and cheaper to buy, its per capita consumption exploded. And so you see the average American consuming 156 lbs per year! There also is a physiologic basis for this. Sugar, specifically fructose seems to have an ability to induce an increase in uric acid. It is speculated that this might be one of the major reasons behind the link between sugar intake and chronic disease.

From colonialism, plunder, slavery, and indentured obesity, hypertension, heart disease, and kidney disease. The history of sugar is inextricably intertwined with the history of modern chronic disease. It is ingrained deeper in our lives than most of us realize. Who would have thought!

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