Say what? In the land of plenty, you may be wondering just how it is even possible that such a deficiency occurs!
For starters, we're told to limit our intake of red meat and avoid too many animal products in our diet - and those that we do eat, well, we're told they should be low-fat products. But, the Harvard Health Newsletter doesn't even address this obvious possible connection to B12 deficiency. Instead they attribute the deficiency on normal aging and eating a vegetarian/vegan diet.
Why they chose not to even state the obvious is beyond me. The only reliable unfortified sources of vitamin B12 are meat, fish, dairy products and eggs.
Vitamin B12 deficiency doesn't happen overnight. In fact it takes years and years to creep up on you. Vitamin B12 is stored in small amounts by the body. Total body store is 2-5mg in adults. Around 80% of this is stored in the liver. Vitamin B12 is excreted in the bile and is effectively reabsorbed. This is known as enterohepatic circulation. The amount of B12 excreted in the bile can vary from 1 to 10ug (micrograms) a day. People on diets low in B12, including vegans and some vegetarians, may be obtaining more B12 from reabsorption than from dietary sources.
Reabsorption is the reason it can take more than 10-years for deficiency disease to develop in people changing to diets low or absent of Vitamin B12. In comparison, if B12 deficiency is due to a failure in absorption it can take just 3 years or less for deficiency disease to occur.
Why do we need Vitamin B12?
- support for the production of red blood cells
- prevention of anemia
- allow nerve cells to develop properly
- help your cells metabolize protein, carbohydrate, and fat
What can indicate a need for more high-vitamin B12 foods?
- red or sore tongue
- tingling or numbness in feet
- heart palpitations
- memory problems
- decreased blood clotting
- decreased reflexes
- difficulty swallowing
- tingling in feet
- weak pulse
- menstrual problems
How do other nutrients interact with vitamin B12?
Vitamin B6 is required for proper absorption of vitamin B12, and deficiency of vitamin B6 has been shown to impair B12 absorption in animal studies.
Conversion of vitamin B12 from its non-active into its biologically active form requires the presence of vitamin E. Individuals at risk for vitamin E deficiency may show signs of vitamin B12 deficiency as well.
Contrary to research from the mid 1970s, supplemental doses of vitamin C above the 500 milligram level do not appear to compromise B12 function.
Excessive intake of folic acid can mask B12 deficiencies, and individuals at risk for vitamin B12 deficiency who are also taking folic acid in supplement form should consult with their healthcare practitioner.
The most recent Recommended Dietary Allowances (RDAs) for vitamin B12 were set in 1998 by the National Academy of Sciences. The RDAs were established for all persons 1 year of age and older. For infants under the age of 1 year, Adequate Intake (AI) levels were set. These AI and RDA guidelines are as follows:
- 0-6 months: 400 nanograms
- 6-12 months: 500 nanograms
- 1-3 years: 900 nanograms
- 4-8 years: 1.2 micrograms
- males 9-13 years: 1.8 micrograms
- males 14 years and older: 2.4 micrograms
- females 9-13 years: 1.8 micrograms
- females 14 years and older: 2.4 micrograms
- Pregnant females of any age: 2.6 micrograms
- Lactating females of any age: 2.8 micrograms
Vitamin B12 deficiency is serious stuff. While taking a supplement may help boost levels back to normal in the body, you're still better off eating real food and choosing foods that contain high levels of B12 - like liver, beef, snapper, shrimp, snapper, scallops, chinook salmon, lamb, cod, halibut, venison, milk, yogurt and eggs.
If you're avoiding red meat and eggs, consider the fish selections above!
Keep in mind, while the Dietary Guidelines for Americans [DGA] encourage you to limit your animal proteins to 5 to 6 ounces each day, this is simply not enough to meet and/or exceed your requirement for Vitamin B12. I've been saying for some time now that the DGA is too low in a number of nutrients for health and well-being. This here is a clear example of how the recommendations to limit animal proteins is potentially affecting health in the United States - if you follow the DGA and limit your animal proteins, you're limiting your intake of Vitamin B12 - a vitamin critical for long-term health!