4 “Healthy” Habits That Can Harm Your Brain

These wellness "tools" may be causing brain issues.

By Austin Perlmutter, MD

In our quest for optimal health, it’s easy to buy into wellness trends that promise rapid gains and simple fixes. Yet some of these “healthy” habits can backfire, quietly undermining the very things they claim to promote. Beyond general health concerns, certain wellness trends may pose an especially concerning risk for brain function. Today we’re exploring four popular trends—sugary “health” foods, unregulated supplements, metric-obsession, and burning incense or scented candles—and the science showing how each can erode brain health.

1.  “Healthy” Ultra-Processed And Sugary Foods

Each year, I attend some of the largest “health food” events on the planet. I see thousands of new products geared towards the health-conscious consumer promising everything from weight loss to improved brain function. Yet many of these seemingly well-meaning products are loaded with junk that has been linked to worse brain health. Specifically, they’re packed with added sugar.

My experience is emblematic of a concerning trend in “healthy” food. Many bestselling products marketed as wholesome—like beverages, granola bars, flavored yogurts, cereals and other snacks—are major sources of added sugar. Excessive added sugar intake has been linked to accelerated cognitive decline and dementia risk. A recent UK Biobank analysis of over 200,000 people found that higher dietary sugar consumption was associated with greater incidence of dementia.

Over time, high-sugar diets may promote inflammation, oxidative stress, and insulin resistance in the body and the brain—key drivers of impaired synaptic plasticity and memory formation. Almost all guidelines agree that we should be limiting added sugar, regardless of the source. The top takeaway here is to read your ingredients list when purchasing a food and avoid highly-processed foods and beverages with high levels of added sugar. Don’t be misled by clever marketing or a veneer of health!

2.  Unregulated Supplements

The supplement aisle is largely self-regulated: manufacturers need only ensure products are many supplements are at risk of containing brain-damaging molecules. When most Americans take supplements, the scope of a potential problem becomes profound. In a survey of 121 Canadian dietary supplements, almost 2% were found to have high levels of brain-damaging heavy metals like lead and aluminum, and in an analysis of about 7,000 women in the US, those using herbal supplements were found to have lead levels that were 10% higher than non-users.

In addition to the overt brain risks posed by contamination with heavy metals, researchers have also drawn attention to the potential that brain health supplements could be contain adulterant pharmaceuticals. Pharmaceuticals including antidepressants, stimulants, anti-anxiety and anti-inflammatory drugs have been discovered across the spectrum of supplements, but especially sexual enhancement and weight loss products. These same types of adulterants are suggested to be a risk in the brain health supplements space.

What can you do to mitigate these concerns? Look for third-party verification by groups like NSF and USP. Look for transparency around testing for heavy metals and other contaminants. Be cautious of purchasing supplements that are only available online from brand new companies. Discuss your supplements with your healthcare practitioner. Avoid supplements that make sensational claims. 

3.  Unrealistic Ideals and Stressful Comparison

Aspects of wellness culture can provide significant benefits in an age where poor health is the default. Yet at the extreme end, overemphasis on unsustainable, unachievable and otherwise impractical advice can lead to significant stress and unhealthy habits, compromising overall health and especially brain health. With the rise of influencer culture, unrealistic comparisons to photoshopped images, hyperbolic lifestyles and sensationalized health advice are everywhere. So how does this impact the brain?

Orthorexia nervosa is a newer description for a pathological obsession with eating healthy foods. An unhealthy effort to eat perfectly can promote emotional stress as well as malnutrition and other negative health implications. Upward comparisons on social media (where we compare ourselves to people who we deem superior to ourselves) are linked to poor mental health. With wellness celebrity content often extolling unrealistic perfect health and physiques, there are potential risks posed to the psychological state of those engaging with these influencers’ content. Recent research finds this may be of particular concern for women.

What do to about this? Limiting social media is always a reasonable option, and curating who you follow and the content you consume is a good plan. Remind yourself that you're seeing the highlight reels of people's lives, and that, especially if they are selling you a wellness product, they are incentivized to create an unrealistic veneer of youthfulness and beauty. Consider transitioning from short-form, attention-capturing social media forms to longer form conversations like podcasts or YouTube. Set time limits for social media consumption.

4.  Incense and Scented Candles

Burning incense sticks and scented candles may seem to create a relaxing ambiance, but they release a cocktail of airborne toxins. Indoor incense combustion generates fine particulate matter (PM₂.₅), polycyclic aromatic hydrocarbons (PAHs), benzene, and carbon monoxide. Research in older adults in community settings found that regular incense exposure was associated with impaired cognitive function and altered brain connectivity on fMRI.

Similarly, Taiwanese research showed that individuals exposed to incense smoke scored lower on the Mini-Mental State Examination test—an independent risk factor for cognitive decline. Scented candles likewise emit volatile organic compounds (VOCs) (e.g., formaldehyde, benzene) and PM₂.₅. Even short-term exposure to an indoor candle has been shown to reduce performance on tests of cognition, a result that has been since verified in a 2025 publication. Scented candles may be particularly concerning because they release VOCs in addition to particulates.

Some reasonable tools to mitigate potential risks of incense and indoor candles include decreasing total burning time and improving ventilation in the home (e.g., opening windows and running an air purifier). If you choose to use indoor candles, unscented beeswax may be a better bet than scented candles, paraffin candles or soy candles. Keeping candle wicks trimmed can also help reduce air pollution.

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