Nutrient Library: Vitamin B12
What does it do?
Vitamin B12 is a water-soluble B vitamin that helps transform fats and proteins from foods into energy and works with folic acid to produce normal red blood cells. An adequate supply of vitamin B12 is also necessary for normal neurological function.
How much do you need?
The following table lists the recommended intake for healthy people based on current scientific information.
|Life Stage Group||Recommended Dietary Allowance/Adequate Intake||Tolerable Upper Intake Level (UL)|
|0-6 mo. |
|Not determinable due to lack of data on adverse effects and concern about inability to handle excess amounts. Source should be from food only to prevent high levels of intake.|
|1-3 y |
|9-13 y |
> 70 y
|9-13 y |
> 70 y
|< 18 y |
|< 18 y |
NOTE: The table is adapted from the Dietary Reference Intakes reports. Recommended Dietary Allowances (RDAs), when available, are in bold type; Adequate Intakes (AIs) are followed by an asterisk(*). RDAs and AIs may both be used as goals for individual intake. RDAs are set to meet the needs of almost all individuals (97 to 98 percent) in a group. For healthy breastfed infants, the AI is the mean intake. The AI for other life stage and gender groups is believed to cover the needs of all individuals in the group, but lack of data means the percentage of individuals covered by this intake cannot be specified with confidence.
UL = The maximum level of daily nutrient intake that is likely to pose no risk of adverse effects. Unless otherwise specified, the UL represents total intake from food, water and supplements.
What are the best food sources?
Vitamin B12 is found naturally in animal-based foods, such as meat, fish, poultry, eggs and dairy foods. Particularly rich sources of vitamin B12 include shellfish, herring, sardines, trout and some game meats. Vegans and strict vegetarians can get B12 from some fortified foods, such as ready-to-eat cereals and meal replacements (e.g., bars and drinks).
What happens if you don't get enough?
Nutritional deficiency of this vitamin is rare among those under 50 years old because the human body can store several years' worth. However, when it does occur it causes pernicious anemia (also known as megaloblastic anemia), a condition in which the body fails to absorb B12 and becomes unableto produce enough healthy red blood cells. Symptoms include low counts of abnormally large red blood cells, fatigue, nerve damage, numbness and tingling of the extremities (e.g. fingers, toes), cognitive changes, a sore tongue or loss of appetite.
Adults over 50 years old are often at risk of not getting enough vitamin B12. This may be because of a decrease in the production of stomach acid with age (which is needed to extract B12 from food) or malabsorption problems due to the presence of atrophic gastritis (a chronic inflammation that causes damage to the lining of the stomach and results in the body's inability to extract vitamin B12 from dietary proteins). Thus, adults over 50 years old are advised to consume foods fortified with vitamin B12 or a supplement containing B12, both of which are more available sources to this population. Consult with your physician if you are worried that this might be you.
Individuals who follow a vegan or strict vegetarian diet (B12 is found in food from animals) and anyone with a digestive problem that impairs absorption of nutrients (e.g., celiac disease, Crohn's) are also at a higher risk of vitamin B12 deficiency. Consult your physician if you fall into one of these categories.
What happens if you get too much?
It's not likely that you will experience harmful effects from consuming too much vitamin B12, because your body can only absorb a small amount of the B12 you receive from foods and supplements. However, moderation is still the best approach, as studies have not specifically looked at the harmful effects of excess vitamin B12.
Lemon-Garlic Shrimp & Vegetables
Here's a healthy twist on shrimp scampi. We left out the butter and loaded the dish up with red peppers and asparagus for a refreshing spring meal. Serve with quinoa, whole-wheat couscous or linguine.
Makes 4 servings
ACTIVE TIME: 35 minutes
TOTAL TIME: 35 minutes
EASE OF PREPARATION: Easy
Heat 2 teaspoons oil in a large nonstick skillet over medium-high heat. Add bell peppers, asparagus, lemon zest and 1/4 teaspoon salt and cook, stirring occasionally, until just beginning to soften, about 6 minutes. Transfer the vegetables to a bowl; cover to keep warm.
Add the remaining 2 teaspoons oil and garlic to the pan and cook, stirring, until fragrant, about 30 seconds. Add shrimp and cook, stirring, for 1 minute. Whisk broth and cornstarch in a small bowl until smooth and add to the pan along with the remaining 1/4 teaspoon salt. Cook, stirring, until the sauce has thickened slightly and the shrimp are pink and just cooked through, about 2 minutes more. Remove from the heat. Stir in lemon juice and parsley. Serve the shrimp and sauce over the vegetables.
NUTRITION INFORMATION: Per serving: 226 calories; 7 g fat (1 g sat, 4 g mono); 174 mg cholesterol; 14 g carbohydrate; 28 g protein; 4 g fiber; 514 mg sodium; 670 mg potassium. Nutrition bonus: Vitamin C (210% daily value), Vitamin A (80% dv), Folate (53% dv), Iron (25% dv). 1 Carbohydrate Serving. Exchanges: 2 vegetable, 3 lean meat, 1 fat.
Roasted Ratatouille with Eggs & Cheese
Served with plenty of crusty bread and a green salad, this is a perfect dish for brunch or a light supper. Roasting is an excellent technique for ratatouille because the vegetables retain a distinct texture, yet the flavors meld. Pay close attention while you are cooking the eggs in the oven; they turn from nicely set to hard as a rock in a flash.
Makes 4 servings
ACTIVE TIME: 25 minutes
TOTAL TIME: 1 hour 40 minutes
EASE OF PREPARATION: Moderate
NUTRITION INFORMATION: Per serving: 402 calories; 21 g total fat (6 g sat, 11 g mono); 227 mg cholesterol; 34 g carbohydrate; 22 g protein; 7 g fiber; 775 mg sodium; 419 mg potassium. 2 Carbohydrate Servings.
MAKE AHEAD TIP: Prepare through Step 4, cover and refrigerate for up to 2 days. Reheat before continuing.
Manhattan Crab Chowder
If you like Manhattan clam chowder, you'll love how delicious our version is when made with crab. Take your time to finely dice the vegetables and the soup will cook faster. Make it a meal: All you need is crusty bread or oyster crackers and a tossed salad and you've got dinner.
Makes 6 servings, about 1 1/2 cups each
ACTIVE TIME: 30 minutes
TOTAL TIME: 40 minutes
EASE OF PREPARATION: Easy
Heat oil in a large saucepan over medium heat. Add onion, fennel bulb, garlic, Italian seasoning, salt and pepper and cook, stirring often, until the vegetables are just starting to brown, 6 to 8 minutes.
Add broth, water and potatoes; bring to a boil. Reduce heat to a simmer and cook until the vegetables are tender, 3 to 5 minutes. Stir in tomatoes, crab and fennel fronds. Return to a boil, stirring often; immediately remove from heat.
NUTRITION INFORMATION: Per serving: 211 calories; 5 g fat (1 g sat, 4 g mono); 88 mg cholesterol; 21 g carbohydrate; 19 g protein; 3 g fiber; 647 mg sodium; 513 mg potassium. Nutrition bonus: Iron (35% daily value), Vitamin C (30% dv), Calcium (15% dv). 1 1/2 Carbohydrate Servings. Exchanges: 1 starch, 1 vegetable, 2 very lean meat, 1 fat
Tips: Look for precooked diced potatoes in the refrigerated section of most supermarket produce departments-near other fresh, prepared vegetables.
We call for convenient canned crushed tomatoes, but you only need 2 cups; store leftover tomatoes in an airtight container for 1 week in the refrigerator or months in the freezer.
From www.eatingwell.com with permission. © 2008 Eating Well Inc.
Good vision is one of the benefits of vitamin A, but this antioxidant is essential to reproduction, bone growth and cellular function, and white blood cell production.
Vitamin E is a fat-soluble vitamin comprised of eight different compounds, each with its own function and use in the body. Its most active form in humans is called alpha-tocopherol which has been associated with reducing the risk of heart disease, certain cancers and cataracts.