Could Low B12 Be Part of Cognitive Decline? My Own Bloodwork Made Me Pay Attention.

A new UCSF study caught my attention because it raised a serious question:

Are the B12 levels we call “normal” really enough, especially as we get older?

That is not a small question.

Many of our customers are people like me. A lot of us are men over 55. We are thinking more about energy, strength, memory, bloodwork, and staying useful as we age. We may not have paid close attention to nutrition when we were younger, but sooner or later something gets our attention.

For me, bloodwork got my attention.

And vitamin B12 was one of the markers I started watching.

The UCSF B12 Study And Cognitive Decline

Researchers at the University of California, San Francisco studied 231 healthy older adults. Their average age was 71. These were not people already diagnosed with dementia or mild cognitive impairment.

The researchers looked at B12 levels and markers of brain and nerve function. What they found was concerning.

Older adults with lower levels of biologically active B12, even when their total B12 was still considered normal, had slower cognitive and visual processing speeds. Brain imaging also showed more white matter lesions in people with lower active B12. White matter lesions are areas of injury in the brain that have been associated with cognitive decline, dementia, and stroke risk.

That does not mean B12 is the only cause of cognitive decline.

But it does mean B12 deserves more attention than many of us have given it.

The researchers said the findings raise questions about whether current B12 recommendations are too low for some older adults. They also pointed out that standard B12 testing may miss more subtle functional problems, especially when people are not severely deficient.

That is what made me stop.

Because my own B12 story lined up with the concern.

My B12 Was Lower Than I Wanted

In February 2025, my B12 was 322 pg/mL.

That was not a number I liked.

Depending on the lab, that may still fall within the “normal” range. But normal did not feel like the right goal to me. I was already changing the way I ate because I had come to believe food was central to health, not a side issue.

My most recent B12 result in 2026 was 574 pg/mL.

That is a big improvement.

And here is the part that matters most to me:

I did not take B12 supplements.

The main thing I changed was my diet.

I cut out seed oils and ultra-processed food. I moved toward a low-carb, higher-fat diet. I started eating more of our own grass-fed beef, eggs, pasture-raised chicken, liver, and real animal fats.

I am not saying my experience proves cause and effect for everyone.

But it proved something to me.

My B12 improved from 322 to 574 without supplements. The biggest change was food. Especially meat.

That gives me some real enthusiasm, because it means the body can respond when we stop feeding it industrial food and start giving it real nutrition again.

Why B12 Matters

Vitamin B12 is essential. The body uses it to make red blood cells, DNA, and nerve tissue. Adults are generally advised to get 2.4 micrograms per day. B12 is found naturally in animal foods, including meat, fish, eggs, and dairy.

That last part is important.

B12 is not naturally found in meaningful amounts in most plant foods. That is why people eating plant-based diets often need supplements or fortified foods.

There is nothing wrong with using supplements when they are needed. Some people have absorption problems. Some have medical conditions. Some take medications that interfere with B12. Those people should work with their doctor.

But I do think we should ask a more basic question first.

Are we eating the foods that naturally contain B12?

For many people, the answer is no.

We have built a food system around cheap calories, seed oils, refined grains, sugar, and fortified products. Then when people run low on nutrients, we act like the solution has to come from a pill bottle.

Sometimes it does.

But often, the first place to look should be food.

Beef And Liver Are Natural B12 Foods

Beef is one of the most practical natural sources of B12.

It is not complicated. It does not require a special routine. It is food people understand. Ground beef, steak, roasts, stew meat, soup bones, and broth all fit into ordinary meals.

Liver is even more concentrated.

Beef liver is one of the richest natural sources of B12 available. Small amounts provide a lot. That is why I started paying more attention to liver myself, even though I did not grow up thinking of liver as a normal part of my diet.

I do not eat huge amounts of it. I do not think most people need to. But I do think liver deserves to come back into the conversation.

For people who are trying to improve their B12 through food, grass-fed beef and beef liver are two of the most reasonable places to start.

Again, this is not a medical claim.

It is a food claim.

B12 comes naturally from animal foods. Beef and liver provide it. My own B12 improved after I made those foods a bigger part of my diet.

That is enough for me to take it seriously.

Why Grass-Fed Beef Matters To Me

At Tyner Pond Farm, we raise 100% grass-fed beef here in central Indiana.

Our cattle are moved through pasture in a managed grazing system. We are not raising animals in a feedlot and finishing them on grain. We are using grass, sunlight, soil biology, and time.

That matters to me.

I do not think all beef is the same. I do not think food is just a list of nutrients on a label. Food comes from a system.

Healthy soil grows better forage. Better forage supports healthier animals. Healthier animals produce food that nourishes people.

That is the system I believe in.

When I look at my own health changes, I cannot separate the food from the way the food was raised. I know the cattle. I know the pastures. I know the work behind it.

And I know what changed in my own diet.

I started eating our beef more consistently. I started eating liver. I started eating eggs and chicken from pasture-based systems. I stopped eating seed oils and ultra-processed foods.

My numbers changed.

That is not theory to me anymore.

The Bigger B12 Problem

The UCSF study suggests this may be a wider issue than many people realize.

It is not only about people with severe B12 deficiency. The concern is that older adults may have B12 levels that look acceptable on paper but are still not enough for brain and nerve health.

That should get our attention.

A lot of people are walking around tired, foggy, weak, or mentally slower than they used to be. There can be many reasons for that. Sleep, stress, blood sugar, medications, alcohol, inflammation, and other health conditions all matter.

But B12 should be part of the conversation.

• Especially for older adults.
• Especially for people eating less meat.
• Especially for people relying heavily on processed foods.
• Especially for people whose lab results are “normal” but not where they want them to be.

That was my situation.

My B12 was not catastrophically low. But it was lower than I wanted...and as this study infers...lower normal probably isn't great.  I changed my diet, and now it is much better.

What I Would Tell Someone Like Me

If your B12 is low, borderline, or lower than you want, talk to your doctor.

Ask about B12. Ask about methylmalonic acid. Ask about homocysteine. Ask whether your symptoms and your bloodwork line up. Do not treat a lab range as the whole story.

But also look hard at your food.

Are you eating real animal foods that naturally contain B12?

Are you eating enough protein?

Are you eating liver or other organ meats at least occasionally?

Are you relying on fortified foods and supplements while still eating seed oils and ultra-processed food?

Those are fair questions.

I am not against supplements when they are needed. But in my own case, I wanted to see what food could do.

My B12 went from 322 to 574. (I've shared my complete bloodwork here)

No B12 supplements.

Just a serious change in diet.

That matters to me.

A Natural Place To Start

If you want to improve your nutrition, grass-fed beef is a practical place to start.

If you want a more concentrated source of B12, beef liver is worth considering.

You do not have to make it complicated. Start with ground beef. Add steak or roasts when they fit your budget. Try small amounts of liver. Use eggs. Make broth. Cook real meals.

This is not a quick trick.

It is a return to food that actually nourishes.

The UCSF study is important because it reminds us that B12 may matter more than we thought, especially as we age. My own bloodwork made it personal. And my own experience made me believe even more strongly that nutrient-dense animal foods belong at the center of this conversation.

I fixed my B12 with diet.

That may not be possible for everyone. Some people need medical help, and they should get it.

But for people like me, who were not paying enough attention to nutrient density, food is the first place I would look.

And I would start with grass-fed beef and liver.

FAQ Section

Why is B12 important as we age?

B12 helps the body make red blood cells, DNA, and nerve tissue. A new UCSF study suggests that lower active B12 levels in older adults may be linked to slower cognitive and visual processing, even when total B12 levels are still considered normal.

What foods naturally contain B12?

B12 is found naturally in animal foods, including beef, liver, fish, eggs, and dairy. It can also be obtained through supplements and fortified foods.

Is grass-fed beef a natural source of B12?

Yes. Beef naturally contains B12, along with protein, zinc, iron, and other nutrients. Grass-fed beef is a practical food-based option for people who want to get more nutrition from real food.

Is beef liver high in B12?

Yes. Beef liver is one of the richest natural food sources of B12. Small servings provide a significant amount.

Did grass-fed beef raise my B12?

I cannot prove that grass-fed beef alone raised my B12. But my B12 improved from 322 pg/mL to 574 pg/mL after I changed my diet, without taking B12 supplements. The major change I made was eating more real animal foods, especially grass-fed beef, liver, eggs, chicken, and traditional fats, while cutting out seed oils and ultra-processed food.

Should I take a B12 supplement?

Some people need B12 supplements, especially if they have absorption issues, certain medical conditions, medication-related depletion, or eat little or no animal food. Talk to your doctor and ask whether additional testing, such as methylmalonic acid or homocysteine, makes sense for you.