Thanksgiving Part 1 — Cranberries

A while back, before I retired from the Division of Nutritional Sciences at Cornell University, I helped write answer for a nutrition Q&A website that we called Nutriquest. Was looking over my files and found a four-part series I wrote for Thanksgiving. Here is the first part, lightly edited.  The next parts will be posted over the coming days.

In the US, the fourth Thursday of November is devoted to a very special holiday, Thanksgiving. The day is notable in that it is our national occasion to give thanks for the food that we have—and to help those who do not have enough food, here in the US and throughout the world.

Because food is such a central part of Thanksgiving, and because the Thanksgiving foods have such an interesting history, weaving together nutrition, agriculture and culture, we thought that we would take the opportunity this week to provide you with a series about the Thanksgiving foods, with a couple of recipes and cooking hints thrown in.


A NUTRIQUEST THANKSGIVING - PART 1

A cartful of Thanksgiving foods—turkey, cranberries, sweet potatoes, yams, corn and lima beans for succotash, apples and pumpkin for pie, as well as lettuce for salad, and carrots and potatoes and onions to put around the turkey—no wonder these boys are rushing home!
We will start our series with cranberries, and present to you a couple of recipes for cranberry sauce— a link to Mama Stamberg's at National Public Radio, and one of our own, for people who prefer their sauce to be low-fat and a deeper red...

Where do cranberries come from?

Cranberries are native to the New England coast, and are one of three berries that are native to North America (the other two are blueberries and Concord grapes). Cranberries grow on vines that, if well cared for, live indefinitely.

Cranberry vines are very particular about their growing conditions, so the areas in North America where they are grown are limited to New England, New Jersey, the Northwest (Oregon, Washington State, British Columbia), Wisconsin and Quebec. The Northeast, Northwest, Wisconsin and Quebec all share the characteristic that the land was covered in glaciers in the last Ice Age, about 10,000 years ago. The retreat of the glaciers provided the ideal land for the formation of cranberry bogs -- layers of gravel, sand and clay, with abundant peat. The gravel, sand and clay provide just the right amount of drainage for these plants that prefer abundant fresh water, and the peat provides the acidic soil that keeps them healthy.

Here's a map of part of Plymouth County Massachusetts that I gleaned from the USDA Natural Resources Conservation Service. Cranberry bogs are indicated by the red outlines. As you can see the areas are near gravel pits and swamps.

What are cranberries good for?

Vitamin C

Long before vitamin C was discovered, and long before the English Pilgrims came to America, Native Americans knew that cranberries could prevent scurvy. In addition to eating cranberries fresh, they combined crushed cranberries, meat and fat into strips which they dried to form pemmican. Pemmican served as a food for winters and for long voyages, when fruits were unavailable.

Scurvy—the disease caused by vitamin C deficiency—was potentially a serious problem through the long cold winters in the Northeast. These winters were particularly long and cold during the "Little Ice Age" that lasted from the 13th to the early 19th centuries. Cold weather and large amounts of snow meant that fresh fruits, the primary source of vitamin C, were not available. Native Americans developed a number of different remedies for preventing scurvy, including the use of tree material, such as sassafras and American spruce, as well as cranberries. [Side note: spruce tip jelly is particularly delicious! and see footnote below about the native American use of spruce*]

Descriptions of scurvy by English and French voyagers, coupled with the descriptions of the native American remedies, led James Lind (1716-1794) to develop the experiments that showed that scurvy was not due to an infection, as had been thought in Europe, but due to a dietary deficiency. only aft er after Lind's death did the British Navy finally followed Lind's recommendation to add lemon juice to the sailors' rations.**

While scurvy may not be common in the US today, thanks to the year-round availability of fresh fruit, cranberries are a particularly good source of vitamin C.

Cranberry juice and urinary tract infections

Daily consumption of cranberry juice appears to be effective in diminishing the chances of developing, or suffering a recurrence of, urinary tract infections. It has long been thought that cranberry juice prevents urinary tract infection by acidifying the urine.

In fact, cranberry juice does not acidify urine in a consistent way—vitamin C by itself is better at that. Rather, cranberry juice works through another mechanism. The first step in the development of an infection requires that that bacteria stick to each other and to tissue surfaces, so that they don't get flushed out with the urine. Cranberry juice prevents this sticking, and thereby prevents the bacteria from getting a foothold in the urinary tract --and thus prevents urinary tract infections

Cranberry juice and cancer

There is intensive research underway to determine whether cranberry juice plays a role in preventing and treating cancer. There are theoretical reasons why it should do so, and some animal data that support this possibility.***

Cranberry juice, vitamin B12, proton pump inhibitors, and older people

Vitamin B12 requires an acid environment to be released from food. People who are using a proton pump inhibitor (two commercial names: Prilosec and Nexium) for heartburn or an acid stomach, or for stomach ulcers, or who are elderly, have very little acid in their stomachs and not enough to enable vitamin B12 to be released. Cranberry juice, because of its acid content, can take the place of stomach acid, and improve vitamin B12 release and absorption. So if you are over 65 or are on omeprazole, it might be a good idea to drink a glass of cranberry juice every day, along with your animal protein or yeast, the source of vitamin B12 in the diet.

So cranberry juice and cranberries are good for me—now how do I make cranberry sauce?

First, my recipe, developed for people who like their cranberry sauce sweet and spicy:

• Wash and then plunge about four cups of cranberries into clear boiling water, just long enough so that they burst, and the skins will come off easily;
• Strain the berries through a strainer (preferably stainless steel so the flavor of the metal doesn't leach into the sauce), and capture the thickened juice;
• Meanwhile, take a medium red onion (or half a large one) and cook it in vegetable oil until the onion is translucent (you can omit this cooking step if you like your onions to taste strong—cooking breaks down allicin, the pungent compound that activates TRPA1, the cold receptor—red onions are sweeter and milder than others, and I happen to like the flavor without the pungency);
• Put the berry puree and drained onions in a food processor, and add the following:

1. a heaping tablespoon or two (or three) of dark brown sugar (how much depends on how sweeeeeet you want your sauce to be);
2. a pinch of fresh ground pepper;
3. a 1/4 teaspoon of cinnamon powder, to taste;
4. a pinch of clove powder;
5. you may also also want to add a peeled segmented orange, but remember to remove all the white strings, which are bitter;
6. and then the secret ingredients—a teaspoon of powdered dark chocolate or chocolate liqueur, and a tablespoon of coffee liqueur or cream sherry, or preferably both to total of about one tablespoon (for those of you who don't drink alcohol, you can substitute two teaspoons of very strong coffee); and a teaspoon of dark balsamic vinegar.
7. At this point I run the food processor to be sure all the ingredients are mixed.

• Finally, the juice of half or so of a lemon—this takes the place of salt.

I should confess here that I don't really measure when I cook—so when I put together this cranberry sauce I taste it after I add each of the spices and the secret ingredients to see if I have the balance right, and I usually end up adding a little more of one or the other. I add the lemon at the end little by little because it brightens the flavors (it activates TRPA1, the cold receptor)—with tastes in between to be sure not to overdo it. If I overshoot, I just add back one of the ingredients that activates the warm/hot receptors, such as brown sugar or a pinch of cinnamon.

• Run the food processor again until the ingredients are thoroughly mixed, then put in a glass bowl, and chill immediately. May be kept for one to three days in the refrigerator.
• Enjoy!

And here's Susan Stamberg's Mama's version of Craig Claiborne's cranberry relish from National Public Radio.

*Note that Jacques Cartier and his companions, in their first winter in what is now Canada (1536), suffered from scurvy, and survived thanks to the remedy prepared for them by local first American women from a tree that was probably a spruce. Samuel de Champlain's men were not so lucky: see Thomas A.Crist, Marcella H.Sorg. Adult scurvy in New France: Samuel de Champlain's “Mal de la terre” at Saint Croix Island, 1604–1605. International Journal of Paleopathology. Volume 5, June 2014, Pages 95-105.
** Peter M. Dunn. James Lind (1716-94) of Edinburgh and the treatment of scurvy.  Archives of Disease in Childhood - Fetal and Neonatal Edition. 1997;76:F64-F65. http://fn.bmj.com/content/76/1/F64

*** Jennifer Clarke, and Laura A. Kresty. Cranberries and Cancer: An Update of Preclinical Studies Evaluating the Cancer Inhibitory Potential of Cranberry and Cranberry Derived Constituents. Antioxidants 2016, 5(3), 27; doi:10.3390/antiox5030027.