Three in 4 Americans have a vitamin D deficiency, according to the Academy of Nutrition and Dietetics. It's a growing problem.
New research finds that those deficient may be at a greater risk of developing Type 2 diabetes.
In a new study published in Diabetes Care, high-risk patients with the highest blood levels of vitamin D were 28 percent less likely to develop Type 2 diabetes than those with the lowest vitamin D levels.
Tufts University researchers studied 2,039 participants in the Diabetes Prevention Program. Unlike past studies that measured vitamin D status only once, blood levels of vitamin D were tested multiple times over an average 2.7 years. After adjusting for other diabetes risk factors, the researchers found that those in the top one-third of vitamin D status were significantly less likely to develop diabetes.
In an epidemiological study conducted by researchers at University of California San Diego School of Medicine and Seoul National University, scientists came to a similar conclusion. Their findings were reported in PLOS One journal online.
Scientists studied a cohort of 903 healthy adults (mean age: 74) with no indications of either pre-diabetes or diabetes during clinic visits from 1997 to 1999, and then followed the participants through 2009. Vitamin D levels in blood were measured during these visits, along with fasting plasma glucose and oral glucose tolerance.
Over the course of time, there were 47 new cases of diabetes and 337 new cases of pre-diabetes, in which blood sugar levels are higher than normal but not yet high enough to be categorized as Type 2 diabetes.
For the study, the researchers identified the minimum healthy level of 25-hydroxyvitamin D in blood plasma to be 30 nanograms per milliliter.
"We found that participants with blood levels of 25-hydroxyvitamin D that were above 30 ng/ml had one-third of the risk of diabetes and those with levels above 50 ng/ml had one-fifth of the risk of developing diabetes," said first author Dr. Sue Park, in the Department of Preventive Medicine at Seoul National University College of Medicine.
Researchers considered people 25-hydroxyvitamin D levels below 30 ng/ml vitamin D deficient. These people, the researchers found, were at up to five times greater risk for developing diabetes than people with levels above 50 ng/ml.
How does it work? Vitamin D could help ward off diabetes by improving the workings of the pancreas, which plays a key role in the disease. In a 2011 randomized trial published in the American Journal of Clinical Nutrition, Tufts researchers found that daily supplementation of vitamin D boosted the function of cells in the pancreas that produce insulin. The study of 92 overweight adults with pre-diabetes tested supplementation with 2,000 IU of vitamin D daily versus a placebo. After 10 weeks, those taking vitamin D saw a 26 percent improvement in functioning of cells in the pancreas, while those in the control group had a 14 percent worsening.
The bottom line? Have your doctor test to see if you are vitamin D deficient. If so, he's likely to recommend a supplement that may, in turn, help reduce your chance of developing diabetes.
Q and A
Q: Is it true that you don't get much nutrition from eating raw spinach, because its nutrients are bound to something called oxalates?
A: This is a no and yes answer. Spinach is endowed with a lot of nutrients and plant compounds, so that answer is no; it is not true about not getting "much nutrition." However, yes, oxalates interfere with the body's ability to absorb the calcium that is found in spinach. Oxalates are naturally occurring molecules in the organic acid family. In addition to spinach, many other foods contain oxalates, such as almonds, sesame seeds, beets, rhubarb, cashew nuts and chocolate. Oxalates can bind to metal ions, especially calcium, which forms a compound called calcium oxalate. This binding process interferes with the body's absorption of calcium. Although spinach is high in calcium (245 milligrams in 1 cup of cooked spinach), calcium absorption is hindered because of the oxalates. Raw spinach still contains other healthful nutrients, such as lutein, vitamin C, vitamin K and folate. Boiling is often suggested to reduce oxalates contained in spinach; however, the actual reduction is small, only about 5 to 20 percent. Spinach contains other nutrients that can be affected by heat and water, such as vitamin C and folate; these will be significantly reduced by boiling as well. Individuals who have a history of kidney stones may have already been questioned about their intake of spinach and other foods that contain oxalates. For most people, however, the non-oxalate nutritional benefits of spinach, raw or cooked, make it a healthy choice.
Information courtesy of Tufts University Health & Nutrition Letter.
RECIPE
There's no reason to wait until January to start eating healthy. Here's a recipe from Hy-Vee for a heart-healthy Honey-Orange Salmon with Roasted Veggies.
HONEY-ORANGE SALMON WITH ROASTED VEGGIES
2 small sweet potatoes, peeled and cut into 3-inch sticks
8 ounces Broccolini spears
1 cup frozen pearl onions, thawed
4 tablespoons olive oil, divided
2 teaspoons chopped fresh rosemary
3/4 teaspoon kosher salt, divided
1/8 teaspoon black pepper
1/4 teaspoon orange zest
2 tablespoons orange juice, divided
1 tablespoon honey
2 cloves garlic, minced
1 dash cayenne pepper
1 pound fresh wild salmon fillet, about 1/2-inch thick
Fresh parsley, chopped, for garnish
Preheat oven to 425 F. Combine sweet potatoes, Broccolini and onions in a large bowl. Drizzle with 2 tablespoons olive oil; sprinkle with rosemary, 1/2 teaspoon salt and black pepper. Toss until well coated. Transfer to a 15-by-10-inch baking sheet. Roast for 15 minutes. Whisk together remaining 2 tablespoons olive oil, orange zest and juice, honey, garlic, 1/4 teaspoon salt and cayenne pepper in a small bowl; divide mixture in half. Push partially roasted vegetables to the edge of the pan. Place salmon, skin side down, in center of pan. Brush salmon with half of the orange juice mixture. Roast for 8 to 10 minutes, or until salmon flakes easily with a fork (145 F) and vegetables are tender. Transfer salmon and vegetables to a platter. Serve with reserved orange juice mixture. Sprinkle with parsley; garnish with orange slices, if desired. Serves 4.
Per serving: 430 calories, 25 grams protein, 17 grams carbohydrates, 29 grams fat, 60 milligrams cholesterol, 2 grams fiber, 9 grams sugar (4 grams added sugar), 450 milligrams sodium.
Charlyn Fargo is a registered dietitian at Hy-Vee in Springfield, Illinois, and the media representative for the Illinois Academy of Nutrition and Dietetics. For comments or questions, contact her at [email protected] or follow her on Twitter @NutritionRd. To find out more about Charlyn Fargo and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.
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