Best food groups: Meats, seafood, fortified foods
Also consider: Fortified cereals, chicken and turkey giblets
What is vitamin B12 and why is it so important? Vitamin B12 is a water-soluble vitamin. It exists in several forms that all contain the mineral cobalt; that is why they are collectively known as cobalamins. The main function of vitamin B12 is to act as a helper or cofactor for critical chemical reactions in the body that produce hormones, proteins, lipids, and red blood cells, and to ensure proper neurological function in the body. Deficiencies in vitamin B12, caused by inadequate intake or due to health challenges, are often manifested as: megaloblastic anemia, loss of appetite, weight loss, fatigue/weakness, depression, dementia, and poor memory.
Did you know? The human body can store several years' worth of vitamin B12 in the liver. This is why deficiencies of this vitamin can be rarer compared to other nutritional deficiencies. However, a B12 deficiency is more likely to happen due to a lack of stomach acid and/or a substance present in the gut called intrinsic factor, which helps the vitamin absorb into the body. This is more common in the elderly.
How much is enough?
The DV for B12 is 6 mcg, based on a 2,000-calorie diet.
Vitamin B12 has a very low potential for toxicity. This, along with the fact that there are no adverse effects associated with excess vitamin B12 intake, has led the Institute of Medicine to not establish a UL for this nutrient. However, the DV for vitamin B12 is 6 mcg per day, which is nearly two and a half times higher than the RDA for adults.
Supplements: Vitamin B12 is commonly added to fortified food, so by eating this food, you are in a way already being supplemented with this vitamin. However, vitamin B12 is commonly found in multivitamins, in vitamin B-complex supplements, or as a stand-alone supplements in tablet, capsule, and sublingual versions.
1. Beef Liver
Whether you go by DV or RDA, beef liver delivers an abundance of B12. Keep in mind that the serving size is 3 ounces. You could easily reduce the portion size to 2 ounces, which would provide about 48 mcg of vitamin B12 and 216 mg of cholesterol.
2. Clams
Clams are an excellent source of iron, manganese, selenium, and vitamin B12, and a good source of copper, phosphorus, riboflavin, and vitamin C.
Don't really like the consistency of clams? Not to worry: A study suggested that the broth of canned clams contains high amounts of vitamin B12. Up to 72 percent of the clams' vitamin B12 can be recovered from the broth! An animal study demonstrated cholesterol reduction in rats that were fed clam extract.
3. Braunschweiger
What's so unique about braunschweiger is that those who don't care for liver may actually like this spreadable form.
4. Crab
Depending on the type of crab, edible meat that you are able to extract from crab ranges anywhere from 10 to 25 percent of the whole crab weight. Crabs are an excellent source of copper, selenium, vitamin B12, and zinc; and a good source of iron, magnesium, niacin, and phosphorus, riboflavin, and vitamin C.
New research is showing there is an inverse relationship between eating shellfish, crab included, and the risk of developing type 2 diabetes. This means the higher consumption of shellfish, the lower the risk is of developing type 2 diabetes.
5. Sardines
Sardines, the first fish to ever be canned, are an excellent source of calcium, niacin, omega-3, phosphorus, selenium, and vitamins B12 and D. They are also a good source of iron, vitamins B2 and B6, and zinc.
Fish consumption has many benefits; however, there might also be some risks, too. A recent study indicated that the benefits—reduction of coronary heart disease, decrease of mild hypertension, prevention of certain cardiac arrhythmias, and sudden death—outweighed the risk of ingesting contaminants found in the fish. Sardines, because they are very small, have the least amount of contaminants and are safer to eat compared to other fish.
6. Oysters
Cooked oysters are an excellent source of copper, iron, and selenium, vitamin B12, and zinc. They are also a good source of magnesium, phosphorus, and riboflavin.
A team of researchers from the United States and Italy found that oysters contain two compounds that have shown in animal studies to stimulate the release of testosterone and estrogen. This may affirm that oysters may help libido after all!
Although some food oysters can produce pearls, they should not be confused with pearl oysters, which belong to a different bivalve family. Oysters change gender several times over the course of their lifetime. They are also natural water filtration systems: one adult oyster can filter more than 60 gallons of water a day!
7. Sockeye Salmon
For more info on this piscatory powerhouse, see page 291. Low maternal B12 levels during pregnancy have been linked to increased infant crying. And a baby who cries all the time could get pretty depressing. Interestingly, low levels of omega-3 fatty acids have also been tied to postpartum depression, so eating two servings of sockeye salmon each week may be just the two-fer for a happy mom and baby!
Did you know?
There aren't many vegetarian sources of vitamin B12, but nutritional yeast, which is grown on blackstrap molasses, contains an active form of the vitamin. It comes as yellow flakes or powder and has a nice cheese flavor; it is wonderful sprinkled on top of popcorn. About 2 rounded teaspoons of nutritional yeast provides the recommended amount of vitamin B12 for adults.
Source: USDA National Nutrient Database for Standard Reference, Release 24