I hope you had a great Thanksgiving. With all the traditional and maybe not-so-traditional foods associated with the holidays, did you wonder how you fared from a nutrient perspective? We had a few of those foods that make you wonder: cheesy grits, corn pudding, and cranberry chutney to go along with the turkey. And don’t forget that pumpkin pie.
Never one to leave well enough alone, I wondered how much nutrition we actually get from traditional holiday foods that typically include more fat and involve more than just lightly steaming vegetables. How much butter and cream did you add to those mashed potatoes? How long did those greens beans cook? How about those marshmallows on the yams?
An even better question is this: Do we end up with any nutrients—especially phytonutrients—from all those vegetables and fruit? Yes, you do, and how you cook the food most likely makes the difference; in fact, one nutrient may increase with cooking! Before we get to all that, one thing’s for sure: Thanksgiving beats Halloween for nutrition.
My question is whether you get any nutrients besides sugar and fat from those marshmallow-covered yams or the green beans swimming in condensed mushroom soup and topped with fried onions from a can. The research on cooking techniques and retention of vitamins, minerals, and phytonutrients in vegetables and fruits is not extensive but overall, the answer is yes. Here’s a synopsis of what I found.
The vitamin that seems to be lost regardless of whether it’s boiled, microwaved, or sauteed is vitamin C. Microwaving seems to preserve the most nutrients, but close to 90% of vitamin C is lost in almost all plant material.
For some nutrients, such as beta-carotene and other carotenoids, starting with fresh vegetables as opposed to frozen seems to help retain nutrients. The amounts of carotenoids in carrots, sweet potatoes, pumpkins, and yams seem to increase when they are cooked. Why? It’s complicated but the phytonutrients are held in a matrix that are broken apart in the cooking process, thus releasing more carotenoids. The same may be true in greens such as spinach and collard greens. Adding bacon doesn’t appear to cause any issues. Using nuts and fruit to make the veggies more attractive can add nutrients as well; for added color and texture, we added slivered almonds and pomegranate seeds to the brussels sprouts with parmesan!
Casseroles may provide the best cooking style when appropriate. Whatever minerals leech out of the vegetables or fruits will be retained in the liquid of the casserole. If you make a casserole from the leftover turkey and more vegetables, or a soup, the nutrients can be retained in there.
This got me to thinking about fruit. What about jellies, jams, chutneys, and butters made from fruit that are sometimes cooked for hours? I’ve begun to bake my own biscuits, which is a challenge onto itself, and also make cranberry chutney for turkey and apple butter for the biscuits. Are there any nutrients left?
While there are not extensive studies on this approach to examining the phytonutrient content of fruit as prepared in jellies and jams, there was one that seemed to fit the research question. In this case, researchers wanted to examined the processing impact on tropical fruits grown in an island off the West Coast of Africa. Just like everywhere, fruit doesn't stay fresh very long and in a poor nation, preserving nutrition to be used later is critical for the health of the population. They estimated that over 40% of the fruit grown was wasted, so they wanted to test the phytonutrient content in jams and jellies made from the fruit. One important part to this study is that the researchers prepared all the jams and jellies the exact same way. How the fruit was cut and processed, what other ingredients were added, how long it was cooked, and how it was preserved were all standardized. Here's what they found.
Mango and tamarind jams preserved catechins while guava jelly contained the most phenolic acids as well as lychee, orange and red guava jams. Banana flower showed a high percentage of tannins and anthocyanins in jams. I’ve never had most of the jellies and jams so is that relevant to what we might typical in the US? Turns out the answer is yes. When compared to jams and jellies from temperate fruit, they turned out as well or better than strawberry, apricot, berry fruits, peach, and apple jams and jellies. It would seem that the jams and jellies we purchase or make would retain enough phytonutrient content to make them acceptable sources in conjunction with eating fruit as well.
The issue we have in the US is that people have not increased their fruit nor vegetable content. In fact, it’s decreased to less than three servings of both per day. What this suggests is that not every vegetable has to be steamed only and fruit can be consumed in other forms other than raw. Yes, the additional sugar has to be acknowledged in caloric intake but in a land addicted to ultra-processed foods, taste and texture matter. If the preparation adds some sugar and fat, who cares as long as people are eating those plant-sources of nutrients?
I also came across research that surprised me. The Environmental Working Group. combs through the USDA database of pesticide and insecticide content of fruits, and vegetables to develop their Dirty Dozen report. The government does the analytics and publishes their findings for all to read. The EWG takes the information and establishes fruits and vegetables with the most pesticides found and those with the least. What is not in the 2023 report are specific F&V that exceed the safe limits of chemicals. Yes, all chemicals except glyphosate are tested for safe levels in animals. Typically, EWG makes a big deal about which ones exceed the safety levels, In that they didn’t, that means that they didn’t find any. That doesn’t meanthese chemicals are absolutely safe and won’t bother some people. It does mean that the levels, usually in the parts per million, don’t exceed safety levels.
But maybe that doesn’t really matter as much as we thought it might, at least, for some pesticides. Based on a recently published study, cooking may reduce the amount of pesticide residues in vegetables. It’s nice to know that blanching, boiling and even stir frying may decrease residues by 10–80%. The research didn’t look at the liquid used for blanching or boiling, so we don’t know whether it’s a chemical change in the structure of the pesticide or it just leaches it out. Still, it was a welcome surprise.
The Bottom Line – Traditional holiday foods do retain beneficial nutrients. They can’t offset all the fat and sugar that were added, but we’re getting some of the vitamins, minerals, and phytonutrients the foods contain. To me, the real lesson is that the way the food is prepared may help you eat more vegetables and fruit. Steamed green beans? Yecch. But covered in a sauce? Maybe that will help get more vegetables into your picky eaters. As long as we control the amount and the frequency, we can feel good about eating holiday foods all year long. Because those nutrients? They’re in there. Thanks for listening but we’re out of time. This is Dr. Chet Zelasko saying health is a choice. Choose wisely today and every day.
References:
1. Food Sci Biotechnol. 2017 Dec 12;27(2):333-342
2. Nutr Bull. 2022 Dec;47(4):538-562. doi: 10.1111/nbu.12584.
3. Foods. 2022 May 18;11(10):1463.
4. Molecules 2018, 23, 2707; doi:10.3390/molecules23102707
