Food cans used to be soldered with lead compounds—so much so that people living off of canned food may have died from lead poisoning. Thankfully, this is no longer a problem in the United States. Lead contamination was actually one of the first priorities of the FDA back in 1906, before it was even called the FDA. It’s great that newspapers now have online archives going back a century, so we can read about landmark historical events like “FDA Proposes Lead-Soldered Cans Be Banned” way back yonder in 1993, going into effect in 1995. Evidently, it was complicated because lead solder was grandfathered in as a prior-sanctioned substance.
Now that the lead is gone, are canned foods healthy? It primarily depends on what’s in the can. If it’s SPAM-dandy, I’d probably pass. Let’s give canned food the benefit of the doubt, though. What about canned fruit?
We know fruits and vegetables in general may help protect us from dying from cardiovascular disease. And when it comes to preventing strokes, fruit may be even more protective. But whether food processing affects this association was unknown. This study found that unprocessed produce (mostly apples and oranges) appeared superior to processed produce. But that was mainly orange and apple juice. No surprise whole fruit is better than fruit juice. What about whole fruit, but just in a can? Dietary guidelines encourage all fruit—fresh, frozen, and canned. But, few studies have examined the health benefits of canned fruit, until now. Canned fruit did not seem to enable people to live longer. In fact, moving from fresh or dried fruit to canned fruit might even shorten one’s life. So, maybe dietary guidelines should stress fresh, frozen, and dried rather than canned.
Why the difference? There’s no more lead, but there is that plastics chemical—BPA—that is used in the lining of most cans, which can leach into the food, and might counterbalance some of the fruit benefits. Recently, blood levels of this chemical were associated with thickening of the linings of the arteries going up to the brains of young adults, for example. Canned fruit is often packed in syrup, as well, with all that added sugar, and the canning process may diminish some nutrients—potentially wiping out 20% to 40% of the phenolic phytonutrients, and about half of the vitamin C.
Maybe one of the reasons citrus appears particularly protective is the vitamin C. It appears the more vitamin C in our diet, the lower our risk of stroke; and the more vitamin C we have in our bloodstream, the lower our risk of stroke. But how did the vitamin C get in their bloodstream? They must have eaten a lot of healthy foods, like citrus, tropical fruits, broccoli, bell peppers.
Therefore, the observed effect of vitamin C on stroke reduction may simply be a proxy for specific healthy foods that lower stroke risk. How could we tell? Give people just vitamin C pills instead, and see if they work. They don’t.
Citrus fruits have all sorts of other compounds associated with lower stroke risk. The whole is greater than the sum of its parts. You can’t capture Mother Nature in a pill. It’s like the apocryphal beta-carotene story. Dozens of studies showed that people who ate more beta-carotene-rich foods, like greens and sweet potatoes, and who had more beta-carotene circulating in their system, had lower cancer risk. But how much money can you make selling carrots? So, they tried giving beta carotene pills to people, and not only didn’t they work; they may have even caused more cancer.
So, I assumed this National Cancer Institute researcher would conclude the obvious: produce, not pills. But no; maybe we should have tried lower dose pills, or maybe alpha-carotene pills, or pills with other phytochemicals, or multiple combinations. After all, it is likely that neither the public nor the scientific community will be satisfied with recommendations concerned solely with mere foods.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.
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