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Musings of a Cancer Doctor

Wide-ranging views and perspective from George W. Sledge, Jr., MD

Monday, November 30, 2020

On the Health Effects of Thanksgiving

By George W. Sledge, Jr., MD​

As I write this, it is Thanksgiving morning in Palo Alto. It is a lovely fall day, a little cool with clear blue skies. It is a deeply strange Thanksgiving, and for me a sad one. My three sons are spread across the continent, in Louisiana, Texas and New York, the first year ever we've not shared a dinner table for Thanksgiving. We will meet on a Zoom videoconference this evening, but it will not be the same.

Thanksgiving is my favorite holiday: uniquely American, not overly commercialized, devoted to families gathering and sharing the Earth's bounty. Or, to put it another way, a holiday devoted to eating too much and watching football on TV. What's not to love?

In addition, there's the comforting history of the first Thanksgiving, celebrated in September or October (not November) of 1621. The Pilgrim fathers had landed in Plymouth, Massachusetts, the previous year and had spent the winter starving, with half of those brought on the Mayflower lost to famine and despair. The following year the survivors had raised crops (especially corn, learned from Native Americans), and after the crops came in decided to hold a harvest banquet.

The banquet was attended by 53 Pilgrims and about 90 members of the Wampanoag tribe, led by their chieftain Massasoit. We know the names of the cooks, which is pleasing: Eleanor Billington, Elizabeth Hopkins, Mary Brewster, and Susanna White. And we have a pretty good idea of what the attendees ate: wild turkey, waterfowl, cod, and corn. The Wampanoag, being good guests, brought five deer they had killed, so venison was on the menu. The historical sources make no mention of cranberries, though the first Pilgrim cookbook, admittedly published a generation later, has a recipe for cranberry sauce, and cranberries are found in local bogs, so I'd like to think that was served as well. An interesting fact: their alternate name for cranberries was bearberry. Bears find cranberries quite tasty. Never get between a bear and cranberries.

The feasting went on for 3 days. The Pilgrims early survival was contingent on the Native Americans, who might easily have wiped them out but instead taught them how to grow corn, beans, and squash. Within 2 generations, the English settlers' ethnic cleansing of Massachusetts largely eliminated their Wampanoag guests, with the exception of a small number who still live on Martha's Vineyard and a few other sites. An important lesson: never assume that, just because someone invites you over for Thanksgiving dinner, they are friends for life. But for those 3 days they were friends.

Why didn't the Wampanoag simply eliminate the Pilgrims before they became an existential threat? It is likely because the Pilgrims landed in an area that had just undergone the massive decimation of the local Native American population. John Smith, who had sailed along the coast of New England in 1614, has found it “well inhabited with a goodly, strong and well proportioned people." But within a few years, a devastating disease outbreak (probably smallpox, though other diseases have been suggested) killed something like nine out of every 10 of the Wampanoag. Did the survivors speak, like our President, of having been infected with the "English virus?" I doubt they considered it a political hoax aimed at undermining the re-election of Chief Massasoit.

Culture, as much as biology, plays a role in infectious outbreaks. One cultural practice that historians point to as possibly important was the existence of sweat lodges, heated rooms where the infected would come to sweat out the disease, surrounded by family and friends. These could become super-spreader events in populations with no prior exposure to foreign microbes. Will 2020 Thanksgiving dinners, where Covid-weary Americans, heedless of CDC warnings, fly across the country to congregate with those they love, turn into modern sweat lodges? I hope not, but fear so.

One can rewrite American history quite easily. No pandemic, and the Pilgrims become unwanted immigrants, easily overwhelmed by a populous, well-organized Wampanoag tribe, backed by a larger Algonquian federation. But I want to believe that the Wampanoag, having like their Pilgrim hosts survived terrible tragedy, felt the need to share and care for their fellow humans. Historical contingencies fascinate, and we are living through one: 2020 without the coronavirus would have gone very differently.

Let me move on to today's Thanksgiving dinner. A survey of thanksgiving dinner dishes I came across suggests that 84 percent of those polled listed turkey as the main source of protein. The side dishes are a more diverse mix: mashed potatoes come in at 34 percent, stuffing at 27 percent, with smaller numbers voting for mac and cheese, green bean casserole, cranberry sauce, and sweet potatoes. Pumpkin pie is the favorite desert by far.

But is all this good for you? That's a legitimate, and somewhat complicated question. I'll try to address it here. And, since I'm a medical oncologist, let me ask if there any cancer implications. As if you didn't already have enough to worry about as 2020 draws to a close.

Let's start with turkey, assuming you are not, like one of my sons, a vegetarian. Turkey is a health food, a great source of protein, as well as Vitamins B2, B3, B6 and B12, selenium and zinc. It has a low glycemic index and is relatively low fat. It is full of tryptophan, which through conversion to serotonin is good for your sleep. Unlike processed meats or barbequed beef, it isn't particularly carcinogenic. Overall, two thumbs up.

The Sledge family has always been big on cranberries for Thanksgiving. Cranberries have been touted as a means of reducing the risk of urinary tract infections through alkalinization of urine, though apparently the number of cranberries this would require is excessive. I've also read, in the August Journal of Agricultural and Food Chemistry, that cranberry extracts have chemopreventive effects against colitis-associated carcinogenesis in mice, which sounds nice, though I'd still want a randomized controlled trial before we start prescribing it to familial polyposis patients. Cranberries also prevent H. pylori colonization in the stomach, so fewer ulcers and stomach cancer. Cranberry juice lowers systolic blood pressure a few points, which is all to the good. Mostly I just like how they taste.

Sweet potatoes are also quite healthy, to my delight. They are high in Vitamins B6, C and D, and contain goodly amounts of iron, magnesium, and potassium. They are loaded with beta carotene, with its presumed chemopreventive effects. Presumed, because Vitamin A failed to prevent carcinogenesis in several randomized controlled trials. But I still give sweet potatoes an “A" for effort.

Pumpkin pie for dessert also gets high marks in my book. Pumpkins are a great source of fiber, better than whole wheat bread. They contain the antioxidants lutein and zeaxanthin, which a Google search assures me may prevent cataracts. I have early cataracts, so I will be sure to eat an extra slice of pie. Like sweet potatoes, they are high in vitamin A (though I probably have enough of that already), as well as riboflavin and folate. But pumpkin pies are pretty fatty, so maybe just one slice after all.

Mashed potatoes, as far as I can tell, are somewhat of a wash. The recently reported NIH-AARP study, which recruited over 566,000 participants and followed them for over 15 years, reported no excess in cancer or cardiac mortality for high potato consumption. The American Diabetes Association considers potatoes an appropriate food for diabetics, as their starches are broken down more slowly than the simple sugars found in so many foods.

I could go on and on, depending on which side dishes you like. Overall, though, Thanksgiving dinner seems pretty healthy, assuming you don't drown in calories. Maybe even good for you from a chemoprevention standpoint. Especially the cranberries. But in this year of COVID-19, the health effects of Thanksgiving dinner are something more than cranberries and pumpkin pie.

Let me end with Abraham Lincoln, that great man who, in addition to saving the Union and ending slavery, issued the 1863 presidential proclamation that established Thanksgiving as an American holiday. Lincoln's proclamation noted the horrors of war through which the United States was passing, but also reminded his fellow citizens of all they had to be thankful for: “the country, rejoicing in the consciousness of augmented strength and vigor, is permitted to expect continuance of years with large increase of freedom."

His proclamation concluded with these lovely words, which I'll quote in full: “I do therefore invite my fellow citizens in every part of the United States, and also those who are at sea and those who are sojourning in foreign lands, to set apart and observe the last Thursday of November next, as a day of Thanksgiving and Praise to our beneficent Father who dwelleth in the Heavens. And I recommend to them that while offering up the ascriptions justly due to Him for such singular deliverances and blessings, they do also, with humble penitence for our national perverseness and disobedience, commend to His tender care all those who have become widows, orphans, mourners or sufferers in the lamentable civil strife in which we are unavoidably engaged, and fervently implore the interposition of the Almighty Hand to heal the wounds of the nation and to restore it as soon as may be consistent with the Divine purposes to the full enjoyment of peace, harmony, tranquility and Union."

To which I can only add my own “Amen." Let those of us who give care, care for those who have become widows, orphans, mourners or sufferers. And let me wish all of you peace, harmony, tranquility and Union, and our world continuance of years with a large increase of freedom. We, like Lincoln's America, certainly need all of these. Some thoughts are for the ages.

  • [email protected]10:19:32 PMHello Dr. Sledge! I so enjoyed your article. I've never thought of pondering the nutritional content of Thanksgiving dishes but your piece sure makes me feel better about having consumed substantial helpings over the years. Hope you had a great gathering, Zoom notwithstanding, and may this Advent be meaningful and joyous for you and your family! Your most grateful patient, Victoria