Health for life

When learning about B12, I was reminded of an article I read a little while ago about B12 deficiency called B12 deficiency: a silent epidemic with serious consequences. The author makes the case that our definition of B12 deficiency may be set too low, and that we can still see symptoms of deficiency at levels that are now considered normal. Currently in the United States, a serum B12 level of less than 100 pg/ml will get you diagnosed with a deficiency, while a range of 200-900 pg/ml is considered normal. But research indicates that those with B12 levels between 200-350 pg/ml, especially older adults, may still show deficiency sypmtoms.

Why is this important? Because B12 is involved in the nervous system and for myelin sheath formation, one of the most common deficiency symptoms is neurological impairment. This could manifest in several ways, including problems with cognition, decreased mobility, or impaired memory. In the elderly, how do we know whether a decline in cognitive function is due to simple aging or due to a subclinical B12 deficiency? We dont. Especially if were A) not testing for serum B12, and B) our deficiency level is set too low.

Interestingly, Japan has increased their cutoff for B12 deficiency to a serum level of 550 pg/ml (confirmed by Wikipedia)... very much higher than our cutoff of 100 pg/ml. Anyone below that level receives treatment. The Japanese also have lower rates of Alzheimers disease and other dementia compared to us here in the States. Its just an association, but there may be a connection there between higher serum B12 in the Japanese and a lack of cognitive decline.

Based on this information, it would seem prudent to keep an eye on B12 status, especially in the elderly. According to the lecture notes, about 15% of the elderly are B12 deficient; the figures in the study cited above place that number at up to 40%. But we dont know how many reside at the low-normal level (a level that would be considered deficient in Japan). B12 supplementation seems to provide far more potential benefit than risk, so I see no reason why we dont give it a shot in those who are subclinically deficient, especially if we can prevent more serious symptoms if levels were to continue to drop.

Before I leave the topic of vitamin B12 (yesterdays post: New Study Links Metformin To Cognitive Impairment, via inadequate vitamin B12), its important to know that you dont have to be taking metformin, or have diabetes at all, to risk a vitamin B12 deficiency.

The National Institutes of Health (NIH) say between 1.5% and 15% of the US population experience vitamin B12 deficiency. Most people over the age of 50 have such poor absorption of the vitamin that the NIH recommends older adults supplement with B12, either by eating fortified foods or taking dietary supplements.

From the NIH Office of Dietary Supplements:
Quick Fact Sheet on Vitamin B12
Professional Fact Sheet on Vitamin B12

Groups that may not be getting enough vitamin B12 or that have trouble absorbing it:

• Many older adults, who do not have enough hydrochloric acid in their stomach to absorb the vitamin B12 naturally present in food. People over 50 should get most of their vitamin B12 from fortified foods or dietary supplements because, in most cases, their bodies can absorb vitamin B12 from these sources.
• People with pernicious anemia whose bodies do not make the intrinsic factor needed to absorb vitamin B12. Doctors usually treat pernicious anemia with vitamin B12 shots, although very high oral doses of vitamin B12 might also be effective.
• People who have had gastrointestinal surgery, such as weight loss surgery, or who have digestive disorders, such as celiac disease or Crohns disease. These conditions can decrease the amount of vitamin B12 that the body can absorb.
• Some people who eat little or no animal foods such as vegetarians and vegans. Only animal foods have vitamin B12 naturally. When pregnant women and women who breastfeed their babies are strict vegetarians or vegans, their babies might also not get enough vitamin B12.

Low levels of vitamin B12 show up as numbness or tingling in the arms and legs, weakness, and loss of balance - symptoms similar to diabetic neuropathy. Other symptoms include constipation, loss of appetite, weight loss, soreness of the mouth or tongue, and megaloblastic anemia. And as we saw in yesterdays post, vitamin B12 deficiency affects cognition, leading to depression, confusion, poor memory, and dementia.

A vitamin B12 deficiency can be detected by a blood test. Also, an elevated mean corpuscular volume (MCV) in a blood test can indicate low B12 status and justifies measurement of serum B12 directly.¹
________¹ Diagnostic Value Of The Mean Corpuscular Volume In The Detection Of Vitamin B12 Deficiency, Scandivavian Journal of Clinical and Laboratory Investigation, February 2000.

A new study has outlined for the first time a biological mechanism by which zinc deficiency can develop with age, leading to a decline of the immune system and increased inflammation associated with many health problems, including cancer, heart disease, autoimmune disease and diabetes.

The research was done by scientists in the Linus Pauling Institute at Oregon State University and the OSU College of Public Health and Human Sciences. It suggests that it’s especially important for elderly people to get adequate dietary intake of zinc, since they may need more of it at this life stage when their ability to absorb it is declining.

About 40 percent of elderly Americans and as many as two billion people around the world have diets that are deficient in this important, but often underappreciated micronutrient, experts say.

The study was published in the Journal of Nutritional Biochemistry, based on findings with laboratory animals. It found that zinc transporters were significantly dysregulated in old animals. They showed signs of zinc deficiency and had an enhanced inflammatory response even though their diet supposedly contained adequate amounts of zinc.

When the animals were given about 10 times their dietary requirement for zinc, the biomarkers of inflammation were restored to those of young animals.

“The elderly are the fastest growing population in the U.S. and are highly vulnerable to zinc deficiency,” said Emily Ho, an LPI principal investigator and associate professor in OSU School of Biological and Population Health Sciences. “They don’t consume enough of this nutrient and don’t absorb it very well.”

“We’ve previously shown in both animal and human studies that zinc deficiency can cause DNA damage, and this new work shows how it can help lead to systemic inflammation,” Ho said.

“Some inflammation is normal, a part of immune defense, wound healing and other functions,” she said. “But in excess, it’s been associated with almost every degenerative disease you can think of, including cancer and heart disease. It appears to be a significant factor in the diseases that most people die from.”

As a result of this and what is now know about zinc absorption in the elderly, Ho said that she would recommend all senior citizens take a dietary supplement that includes the full RDA for zinc, which is 11 milligrams a day for men and 8 milligrams for women. Zinc can be obtained in the diet from seafood and meats, but it’s more difficult to absorb from grains and vegetables – a particular concern for vegetarians.

“We found that the mechanisms to transport zinc are disrupted by age-related epigenetic changes,” said Carmen Wong, an OSU research associate and co-author of this study. “This can cause an increase in DNA methylation and histone modifications that are related to disease processes, especially cancer. Immune system cells are also particularly vulnerable to zinc deficiency.”

Research at OSU and elsewhere has shown that zinc is essential to protect against oxidative stress and help repair DNA damage. In zinc deficiency, the risk of which has been shown to increase with age, the body’s ability to repair genetic damage may be decreasing even as the amount of damage is going up.

Medical tests to determine zinc deficiency are rarely done, scientists say, and are not particularly accurate even if they are done. The best approach is to assure adequate intake of the nutrient through diet or supplements, they said, especially in the elderly.

Even though elderly people have less success in absorbing zinc, the official RDA for them is the same as in younger adults. That issue should be examined more closely, Ho said.

Levels of zinc intake above 40 milligrams per day should be avoided, researchers said, because at very high levels they can interfere with absorption of other necessary nutrients, including iron and copper.