A new report from scientists at the University of Michigan calls for an increase in the recommended daily allowance of Vitamin C in our diets.

The scientists say they have found compelling evidence that the U.S. RDA of Vitamin C should be increased to 200 milligrams per day for adults, up from current levels of 75 milligrams for women and 90 for men.

They cite a slew of research, including a recent analysis of 29 human studies that indicate that healthy levels of Vitamin C can support immune function, reduce inflammation which can lead to conditions such as atherosclerosis, and significantly lower blood pressure. One recent analysis of 29 human studies showed that daily supplements of 500 milligrams of Vitamin C significantly reduced blood pressure. High blood pressure is a major risk factor for heart disease.

The Michigan scientists noted that an optimum diet with the recommended 5 to 9 daily servings of fruits and vegetables, along with a 6-ounce glass of orange juice, could provide 200 milligrams of Vitamin C a day. But most Americans miss the mark when it comes to this optimum diet.

Most of us know that orange juice is a great source of Vitamin C, but many fruits and veggies also serve as excellent sources of this vital antioxidant nutrient. One that many Americans are unfamiliar with is jicama, a root vegetable enjoyed in Mexican and Central American cuisine with a delightfully crunchy texture and flavor similar to a water chestnut.

Jicama is very low in calories – only 35 per 100g serving – and an excellent source of oligofructose inulin, a soluble dietary fiber which does not metabolize in the human body (this makes it an excellent snack food for diabetics and dieters). Jicama is rich in Vitamin C, providing about 20.2 mg (34 percent of the current RDA) per serving. It also is a great source of the micronutrients magnesium, copper, iron, and manganese.

Look for jicama in your grocery store, Asian or Mexican food market. At home, store them as you would potatoes, keeping them in a cool, dark place for up to 3-4 weeks – but be careful not to keep them too cold or the starch will convert to sugar

This recipe for Tangy Jicama Slaw is quick, convenient and packs a mighty Vitamin C punch with the main ingredient plus the addition of lemon and lime – potent Vitamin C partners.  Make ahead and pack it for lunch, or take it to your next summer picnic.

Tangy Jicama Slaw


  • 1 jicama, peeled and chopped
  • 1/4 cup fresh cilantro leaves, minced
  • 1 large lime, juiced
  • 1 lemon, juiced
  • 1 (11 ounce) can mandarin orange segments, drained, liquid reserved
  • salt to taste


Combine the jicama, cilantro, lime juice, lemon juice, and mandarin orange segments with a small amount of the syrup from the can in a bowl; mix to evenly coat. Allow mixture to sit 10 minutes. Season with salt and stir just before serving.

Nutrition Analysis

Amount per serving: Calories 67, Total Fat 0.2g, Cholesterol 0mg

What is your preferred source of Vitamin C?

Science Daily