Some
things never change. My daughters still think I drive too
slowly. Yet some things do change, especially in the field of
nutrition. For example, we used to think that deficiencies of
vitamin B-12 were rare except among strict vegetarians or
people with an autoimmune disease called pernicious anemia.
New
evidence now indicates that if you’re on this list, you may
be at risk for a B12 deficiency: 50 years or older (we can
lose the ability to absorb vitamin B12 as we age), vegetarian
or vegan (B12 is not found in plant foods), take metformin (a
diabetes medication that can reduce the body’s ability to
absorb B12), have any type of intestinal disorder or stomach
surgery such as gastric bypass (vitamin B12 needs a
well-functioning gut to be absorbed), take anti-acid medicines
or aspirin, ibuprofen or similar types of pain relievers (some
meds can reduce the effectiveness of stomach acids to digest
and absorb B12).
Although
it is only required in micro amounts, vitamin B-12 is vital to
the formation of healthy red blood cells and it helps build
everything from genetic material (DNA) to hormones and other
proteins. Perhaps most notable is B12’s role in our nervous
system — all the pathways that help us to think, move and
speak. A deficiency of vitamin B12 can cause the brain to
malfunction and lead to dementia, for example.
Vitamin
B-12 (also known as cobalamin because it contains the mineral
cobalt) also helps keep our homocysteine levels in check. High
amounts of homocysteine are associated with inflammation that
can lead to heart disease.
For most
of us, the most reliable sources of B12 are animal foods
including fish, poultry, meat, eggs, milk, cheese, and yogurt.
Just 3 ounces of cooked clams, for example, provides more than
a thousand times our recommended intake of vitamin B-12,
according to the USDA Nutrient Database.
Other
reliable sources include B12 supplements or fortified foods
such as cereals and nutritional yeasts. People with pernicious
anemia or other disorders that prevent them from absorbing
vitamin B12 in the stomach may need to rely on regular
injections of this important nutrient directly into the blood
stream.
How much
vitamin B12 we need in a day may also be changing. New
evidence suggests the current recommendation may be too low to
accomplish all its vital functions.
In the
meantime, here is a hint when talking to your doc about
testing your vitamin B-12 levels. Blood tests for vitamin B-12
may not tell the whole story, according to recent research.
According to the National Institutes of Health, additional
laboratory tests which include homocysteine and methylmalonic
acid values may also be needed to reliably detect low levels
of vitamin B-12.