Is Your Vitamin B12 Level Low?

If you are 50 or older, Uncle Sam suggests you consider vitamin B12. Here’s why and how to effectively incorporate it into your diet.

With the recent release of the federal Dietary Guidelines for Americans, individuals aged 50 and above are advised to increase their intake of vitamin B12, either through fortified foods or supplements. An expert remarked that we can expect a surge in products highlighting their B12-fortification as this recommendation takes root. Before this trend hits the grocery shelves, let’s explore the essentials about vitamin B12. Do you really need more? And why can’t older adults simply acquire sufficient B12 through diet alone?

According to Dr. Irwin H. Rosenberg, MD, editor of the Tufts University Health & Nutrition Letter, many may not realize the widespread deficiency of vitamin B12 among older adults. Research indicates that 15% to 30% of older individuals may have low B12 levels.

Dr. Rosenberg recently co-chaired a World Health Organization (WHO) consultation on B12 and folic acid, recognizing the deficiency as a global health concern. A contributing factor is the worldwide shortage of animal proteins, which are primary sources of B12. In the U.S., vegans and vegetarians who do not consume dairy or eggs should be particularly cautious of this deficiency since B12 is predominantly found in animal-based foods.

So, what constitutes low vitamin B12 levels? A blood test is required for accurate measurement. Levels below 150 picograms per milliliter (pg/mL) indicate deficiency, while those between 150 and 300 pg/mL are considered uncertain.

The recommended daily allowance (RDA) for adults is 2.4 micrograms (mcg), with higher needs for pregnant or lactating women. This amount can be found in approximately three ounces of beef or three glasses of milk. On average, most Americans consume slightly more than this, about 3.4 mcg daily. However, the Daily Value (DV) indicated on nutrition labels for B12 is higher, at 6.0 mcg. Dr. Rosenberg notes that this figure is based on outdated information and would be revised if the U.S. Food and Drug Administration followed more current recommendations from an Institute of Medicine panel he chaired three years ago. Currently, Dr. Rosenberg is part of a National Institutes of Health (NIH) expert panel working on B12 measurement standards.

The Acid Test
So, why this emphasis on B12? As individuals age, the ability to absorb B12 from food diminishes, largely due to a decline in stomach acid production necessary for B12 utilization.

Despite being a water-soluble vitamin, B12 in foods such as meat, fish, poultry, eggs, and dairy is bound to proteins. In the stomach, hydrochloric acid and the enzyme gastric protease free this B12 for absorption. Consequently, individuals with low stomach acid levels may struggle to extract adequate amounts of dietary B12.

The B12 added to fortified foods, like breakfast cereals, is different. This synthetic form is often in a free state, making it easier for the body to absorb.

Atrophic gastritis, which reduces hydrochloric acid secretion in the stomach, impacts 10% to 30% of older individuals. Consequently, the Institute of Medicine recommends that those over 50 primarily obtain their B12 from fortified foods and supplements. Without a blood test, determining if you’re meeting your B12 needs through diet can be challenging. However, one bowl of fortified cereal—once you check the label—can supply most people over 50 with their daily requirement. Other B12-fortified options include soy milk and meat substitutes.

Moreover, even individuals with sufficient stomach acid may still face B12 absorption challenges. Dr. Rosenberg notes that many people take proton-pump inhibitors for indigestion or acid reflux, which inhibit gastric acid production. This includes medications like Prilosec and Prevacid, along with H2 receptor antagonists like Tagamet, Pepcid, and Zantac—all of which can hinder B12 absorption.

B12, Your Body, and Your Brain
What are the consequences of insufficient vitamin B12? This vitamin is vital for healthy blood cell formation, neurological function, and DNA synthesis. According to the NIH, B12 deficiency signs may include anemia, fatigue, weakness, mouth sores, constipation, appetite loss, and weight loss. Neurological symptoms can manifest as numbness, tingling in extremities, and balance issues. Research indicates B12 deficiency might also be linked to depression and cognitive decline, including confusion and poor memory.

Interestingly, the symptoms of B12 deficiency can overlap with those related to Alzheimer’s disease, leading to questions about whether similar nutritional factors are involved in both conditions.

While some studies have shown that B12 supplementation can lower homocysteine levels—an amino acid associated with both Alzheimer’s and cardiovascular diseases—the direct correlation between B12 and dementia development remains unclear. A study published in 2010 in the journal Neurology discovered a link between elevated homocysteine levels and an increased Alzheimer’s risk, whereas higher B12 levels seemed to reduce this risk, especially in older individuals.

However, reviews from the Cochrane Library and other systematic analyses found insufficient evidence to claim that B12 can prevent dementia. This conclusion also extends to B12 combined with folic acid or vitamin B6.

The same uncertainty surrounds the relationship between B12 and heart disease. While B12 may lower homocysteine, studies indicate it does not significantly reduce cardiovascular risk. The American Heart Association has stated that current evidence is inadequate to support a role for B vitamins in lowering cardiovascular risk.

Conversely, the National Library of Medicine rates vitamin B12 as possibly effective in combatting age-related macular degeneration (AMD). Some research suggests a connection between additional B vitamins and a decreased risk of this leading cause of blindness in older Americans. Other nutritional strategies for reducing AMD risk have stronger backing and deserve consideration alongside vitamin supplementation. (See page 8 for more in-depth information).

B12 Busts
Claims surrounding vitamin B12 supplements often stand on shaky ground. Despite B12’s role in energy metabolism, which leads to marketing it as an energy enhancer, the NIH finds no substantial evidence supporting performance improvements in individuals without a nutritional deficit.

The National Library of Medicine considers vitamin B12 possibly ineffective for sleep disorders and stroke prevention. There is insufficient evidence to rate the effectiveness of B12 in various additional treatments, including shaky-leg syndrome, eczema and psoriasis, allergies, and cancer prevention. A 2009 analysis discussing homocysteine-lowering trials in Norway discovered an increased cancer risk among participants receiving B12 supplements.

It’s essential to ensure adequate vitamin B12 intake, but more isn’t always better. The Institute of Medicine has not established a Tolerable Upper Intake Level (UL) for B12; no adverse effects from excess intake have been reported in healthy individuals. However, your body can only absorb a limited amount—approximately 10 mcg of a 500 mcg supplement is typically processed effectively by a healthy system.

Individuals with Leber’s disease, a hereditary retinal condition, should avoid taking B12 supplements. Those diagnosed with pernicious anemia should only take this vitamin under medical supervision.

Beyond medications, various factors can also affect B12 absorption. High alcohol consumption and potassium supplements may hinder absorption, while vitamin C could potentially destroy dietary B12; it’s best to space these apart by at least two hours.

For most individuals, concerns about vitamin B12 can be easily managed, and any supermarket hype should be regarded with skepticism. If you’re 50 or older, a daily serving of fortified cereal or a B12 supplement containing at least 2.4 mcg should suffice. While vitamin B12 may not have the miraculous properties some claim, it’s undeniably crucial for your health—so be wise about your B12 intake.