Understanding the Hidden Risks of B12 Deficiency in Your Healthy Diet

Vitamin B12 deficiency is far more common than most people realize—and it often flies under the radar for years. Many assume low B12 only affects vegetarians or people with poor diets, but the truth is more surprising: most B12 deficiencies are not caused by low intake, but by poor absorption. That’s why so many otherwise health-conscious adults remain deficient without knowing it.

Why absorption matters more than intake

Vitamin B12 absorption is a multi-step process. First, adequate stomach acid is needed to release B12 from food. Then, a specialized carrier protein called intrinsic factor, produced in the stomach, binds to B12 so it can be absorbed in the small intestine. When either of these steps is compromised, B12 levels can quietly fall—regardless of how much you consume.

Several common conditions interfere with this process, including:

• Low stomach acid (common with aging)

• Chronic gastritis or stomach ulcers

• Celiac disease or Crohn’s disease

• Irritable bowel syndrome

• Age-related stomach atrophy

• Long-term use of acid-reducing medications

Because these issues develop gradually, B12 deficiency often goes unnoticed until symptoms become disruptive.

Warning signs you shouldn’t ignore

B12 plays a critical role in nerve function, red blood cell production, and brain health. When levels drop, symptoms can be subtle at first and easily dismissed as “normal aging” or stress. Common warning signs include:

• Persistent fatigue or weakness

• Brain fog, memory issues, or difficulty concentrating

• Numbness or tingling in the hands and feet

• Balance problems or frequent falls

• Mood changes, anxiety, or depression

• Pale skin or shortness of breath

• A burning or sore tongue

Left untreated, long-term B12 deficiency can contribute to nerve damage, cognitive decline, anemia, and increased fall risk—making it a critical longevity issue.

Dietary Sources and Risk Factors

Vitamin B12 is abundantly found in liver and other organ meats, clams, shellfish, sardines, beef, poultry, fish, and some fermented foods and cheeses. Those who do not consume animal products are at a greater risk and often need supplements to fulfill their basic requirements.

Nonetheless, individuals who frequently consume these foods might still experience deficiencies if their absorption is compromised, particularly those over the age of 50.

The longevity takeaway

If you’re experiencing unexplained fatigue, neurological symptoms, or cognitive changes, B12 deficiency deserves a closer look. Blood testing can help identify low levels, but addressing absorption—not just intake—is often the key to restoring optimal health.

B12 deficiency is common, silent, and highly correctable once identified. Catching it early can protect your brain, nerves, and energy levels for decades to come.