A vegan diet is often promoted as one of the healthiest ways to eat, but that doesn’t mean it’s the healthiest choice for every person—or that it remains beneficial over the long term. In some individuals, years of avoiding animal foods can contribute to chronically low cholesterol and inadequate fat intake, potentially affecting brain function, hormone production, and overall health. Cholesterol isn’t simply something to lower at all costs; it is an essential building block for every cell in the body, especially the brain. If someone develops cognitive symptoms while following a long-term vegan diet, evaluating cholesterol levels and nutritional status should be part of the clinical picture.
A Case That Challenges Conventional Thinking
I recently worked with a patient who had followed a vegan diet for many years because they genuinely believed it was the healthiest way to eat. This wasn’t a philosophical or ethical decision—it was based on the belief that eliminating animal foods would optimize long-term health.
That belief is understandable. Today, if someone searches online for evidence supporting a vegan diet, they will find countless articles explaining its benefits. Likewise, someone searching for reasons not to eat vegan will find an equally convincing collection of information supporting the opposite conclusion. The internet often reinforces what we are already inclined to believe, which is why discernment becomes so important.
The goal isn’t to defend one dietary philosophy over another. The goal is to ask whether a particular approach is actually working for the individual sitting in front of you.
Vegetables Matter, But They Aren’t the Whole Story
None of this diminishes the importance of vegetables. Vegetables provide vitamins, minerals, antioxidants, and phytonutrients that human health depends on. Most people simply cannot thrive without them.
Whether we consume an animal that has consumed these nutrients, or we obtain them directly from plants, those nutrients remain essential. While vegetables are foundational to good nutrition, many people also benefit from nutrient-dense animal foods that provide fats, cholesterol, complete proteins, and other nutrients that can be difficult to obtain—or adequately convert—from plant foods alone.
The challenge comes when a dietary strategy that appears healthy on paper slowly creates nutritional deficiencies over many years.
Extremely Low Cholesterol Is a Bigger Problem Than Many People Realize
The real concern wasn’t simply that this patient had followed a vegan diet—it was what that diet appeared to have done over time. Their total cholesterol measured just 91 mg/dL, a level that can have important implications for brain health and overall physiology.
For many people, seeing a low cholesterol number might sound like excellent news. However, in this context, it represented a significant nutritional concern. When someone has very low cholesterol alongside symptoms such as poor cognitive function, fatigue, or hormonal issues, cholesterol itself deserves attention.
Cholesterol has developed an undeserved reputation as something the body should eliminate whenever possible. In reality, cholesterol is indispensable. Your body uses cholesterol to produce cell membranes, steroid hormones, vitamin D, bile acids for digestion, and the structures that support healthy brain and nervous system function.
Without enough cholesterol, these systems simply cannot function optimally.
Your Brain Depends on Cholesterol
One of cholesterol’s most important jobs is supporting the brain. Approximately 20% of the body’s total cholesterol is found in the brain, where it plays a critical role in maintaining neurons, supporting synapse formation, and allowing nerve cells to communicate effectively.
The brain itself is composed largely of fat. When cholesterol levels become chronically deficient, it is reasonable to ask whether the brain is receiving the raw materials it needs for maintenance and repair.
If someone says, “My brain doesn’t feel like it’s working correctly,” it is worth considering whether nutritional deficiencies—not just neurotransmitter imbalances—could be contributing to that experience. The brain cannot build healthy cell membranes out of nutrients that simply aren’t available.
As I often tell patients, these aren’t arbitrary rules; they’re simply how the human body was designed to function. Cholesterol is fundamental to maintaining healthy brain tissue and the countless microscopic processes that allow neurons to communicate with one another.
The importance of cholesterol extends far beyond a standard lab value. To learn more about cholesterol’s role in the body and why optimizing cholesterol levels requires looking at the bigger picture, check out this post: The Cholesterol Connection: Learn the Hidden Truth Behind This Amazing Molecule.
Higher cholesterol has also been associated with a lower risk of dementia in older adults in several observational studies. While cholesterol is only one piece of the puzzle, it reminds us that extremely low cholesterol is not necessarily a marker of optimal health—especially when neurological symptoms are present.
Fear, Nutrition, and Confirmation Bias
Nutrition discussions often become emotional because people naturally search for information that confirms what they already believe. If someone is convinced a vegan diet is healthiest, they’ll quickly find evidence supporting that view. If someone believes the opposite, they’ll find evidence supporting that instead.
Good clinical thinking requires holding multiple possibilities in mind before reaching a conclusion. That’s true not only in nutrition but in medicine as a whole.
Fear tends to narrow our thinking. When people become anxious about food, cholesterol, saturated fat, or animal products, they often stop evaluating new information objectively. Even highly intelligent people can make poorer decisions when they are operating from a place of fear because stress changes how we process information.
Our job as clinicians is to help patients step back from fear and ask a better question:
Is this approach actually working for your body?
Strategy vs. Tactics in Nutrition
One concept I often come back to is the difference between strategy and tactics.
Strategy is the big-picture plan. Tactics are the individual day-to-day decisions. Choosing a vegan meal on a random Tuesday isn’t necessarily problematic. Following a restrictive diet that leaves someone nutritionally depleted after many years is an entirely different issue.
What seems like a healthy tactic in the moment doesn’t always support a healthy long-term strategy.
This patient chose a vegan diet because it seemed like a healthy daily tactic. But when that tactic was repeated year after year during critical periods of growth and early adulthood, the long-term strategy ultimately failed to support the body’s needs.
Clinicians have to evaluate results—not just intentions.
Individualized Nutrition Always Wins
After reviewing this patient’s history and laboratory findings, it became clear that continuing a vegan diet was no longer serving their health. Because the diet wasn’t rooted in ethical or spiritual beliefs, the patient was willing to gradually reintroduce nutrient-dense animal foods.
This wasn’t about promoting one dietary label over another. It was about restoring the nutrients the body had been missing.
Improving brain health, supporting hormone production, rebuilding healthy cell membranes, and optimizing neurological function all require adequate nutritional building blocks. For this patient, increasing dietary fats and animal-based nutrients became an important part of that process.
Even something as simple as enjoying bacon again became a reminder that food can nourish both the body and quality of life. Early improvements suggested the body was responding positively, although meaningful recovery would still require time.
The Bigger Lesson
Nutrition should never become ideology. Every dietary pattern has strengths, limitations, and situations where it may or may not be appropriate.
The goal isn’t to convince every patient to eat one particular way. The goal is to identify what their body actually needs.
Rather than asking whether a diet is popular or widely recommended, we should ask whether it is supplying the nutrients that person’s body needs to thrive. Laboratory findings, symptoms, and physiology often tell a much more complete story than dietary labels alone.
When laboratory findings, symptoms, and physiology all point in the same direction, clinicians should be willing to reconsider assumptions—even widely accepted ones.
The best nutrition plan isn’t the one that’s most popular online. It’s the one that provides the nutrients necessary for that individual to build a healthy brain, healthy hormones, and healthy cells over the long term.
Looking for Personalized Support?
If you or someone you love is struggling with brain fog, mood swings, fatigue, hormonal imbalances, or health concerns that may be related to nutritional deficiencies, Dr. Andrew Rostenberg can help.
Through Red Mountain Natural Medicine in Boise, Idaho, Dr. Rostenberg works with patients to evaluate the underlying factors contributing to their symptoms, including nutrition, laboratory findings, and overall metabolic health. He sees patients both in person at his Boise clinic and via telemedicine. Learn more or schedule a consultation at Red Mountain Natural Medicine.
