The conventional medical wisdom is that we eat too much salt and should try to lower our salt intake. Although I am far from rabid on the subject, I’ve been on that bandwagon. If you follow this blog, you may recall my recent post on how much salt is in the foods we eat and how we can lower the amount of salt by eating more home cooked food. I also found some surprising facts about which foods have more sodium in them.
But in a New York Times article, science writer Gary Taubes points out that the research behind the “health improves when you lower salt intake” movement is far from airtight. In fact, there is research supporting the opposite conclusion; that reducing salt intake to what the health establishment-suggested reasonable upper limit may actually be harmful in some respects.
Taubes’ article is well worth reading for at least 3 reasons:
- He makes a good case for debating the pros and cons of the issue, rather than accepting the lower-intake-is-better advice on faith or from a doctor who may be taking it on faith.
- Reviewing the studies on which the lower-intake-is-better camp relies, he points out that while the rats in 1 study may have developed hypertension, they got the equivalent of 60 times the amount of salt consumed by the average American.
- His review of this salt intake issue reminds us that conventional medical wisdom changes over time, and that what is absolute truth in one decade may become less accepted, or even laughable, in subsequent decades.
This controversy reminds me of a wise bit of advice from my own mother about medical dogma. In the 1970s medical experts and the government found that the artificial sweetener saccharin was carcinogenic. As a result of scientific studies showing that it caused cancer in rats, foods with saccharin were required to have a warning label. “Use of this product may be hazardous to your health. This product contains saccharin, which has been determined to cause cancer in laboratory animals.”
The warning made saccharin officially a food villain and it certainly did scare me. At the time it came out, I occasionally drank diet soda with saccharin. So I asked my mom, a biochemist and altogether reasonable person, what she thought of the whole saccharin-causes-cancer brouhaha. She said the rats in the saccharin studies were given huge amounts of the artificial sweetener. In her view, the resulting conclusion was about as useful as giving the rats too much water and finding that H2O causes medical problems and should be restricted. My mother wasn’t saying that there would be no ill effects from eating huge amounts of saccharin, but just that she doubted the studies’ conclusions and questioned whether, in any event, they were relevant to normal people, eating normal amounts of artificially sweetened food.
Look behind broad pronouncements, be skeptical, check the primary source and question. That approach is common sense, but it certainly did not yield an accepted result on the safety of saccharin 20+ years ago.
The warning stayed on products with saccharin for several decades. But in 2000 legislation repealed the warning label requirement because the rat-saccharin studies were discredited. Moreover, it turns out that the biological differences between rats and human reactions to the sweetener meant that even if the dosage issue is ignored, the cancers rats developed have no relevance to humans. No studies on humans found a link between saccharin and cancer in people. Saccharin got the medical legislative equivalent of a reversal of its conviction and what looks pretty close to an apology on the National Cancer Institute website.
I’m still not going to eat so much salt that I have to drink water until I’m bloated to avoid feeling parched. And much as I like potato chips and Snickers bars, there are other reasons (besides the evils of salt) to limit my intake of those snack foods. But my mom has taught me well. And now I’m on notice that the amount of salt I eat is yet another area where healthy skepticism is the sensible approach.