"Foods That Make You Stupid": Misunderstanding or Fact? What Color, Sweetness, and Umami Do to the Brain

Introduction—Beyond the Strong Headline

"Brain Constipation—This Food Makes People 'Stupid'." Lively headlines like these stimulate our anxieties and urge to click. A German article dated September 5, 2025, listed "culprits" from sugar to azo dyes, MSG (glutamate), aspartame, vitamin supplements, and citric acid, suggesting risks of memory decline and dementia. However, science is always more modest than headlines. This article aims to clarify "what is known and what is exaggerated" by comparing the original claims with primary research and evaluations by public institutions.Op-Online

Sugar and Ultra-Processed Foods: A "Quiet Headwind" for the Brain

Point: There is increasing evidence suggesting that a diet high in excessive sugars and ultra-processed foods (UPF) can negatively affect attention, mood, and memory through vascular, metabolic, inflammatory, and gut-brain axis pathways.

The German Brain Foundation warns that excessive intake of UPF may increase the risk of stroke, dementia, and Parkinson's. While mostly based on observational studies and not definitive causation, there is a growing consensus that "moderation is prudent."hirnstiftung.orgHealthcare in Europe

Azo Dyes (Tartrazine, etc.): Managed with "Warning Labels" in the EU

The 2007 Southampton study suggested small effects on activity and attention in some children from a mix of six synthetic dyes plus sodium benzoate. While EFSA considers the evidence "limited," the EU still mandates warning labels for the dyes in question, stating they "may have an adverse effect on activity and attention in children" (not a ban, but labeling). Old fragmented information like "Norway bans it" has practically converged under EU labeling rules.EFSAEPHA

MSG (Glutamate): Don't Confuse "Umami" with Safety Margins

MSG is an "umami" derived from amino acids found in nature and within the body. In 2017, EFSA set a group ADI for E620–E625 (glutamate and its salts) and found no genotoxicity concerns at usual intake levels, concluding that issues are limited to "short-term symptoms from excessive intake (including individual sensitivity)." Long-term neurotoxicity or dementia causation is not established. Given the potential for misunderstanding, avoiding excessive intake and keeping information updated is crucial.EFSAEFSA Journal

Aspartame: IARC's "Possibility" vs. JECFA/FDA's "Dose Management"

In 2023, IARC classified aspartame as 2B (possibly carcinogenic). Meanwhile, JECFA maintained an ADI of 0–40 mg/kg body weight/day, and the FDA expressed a similar stance. This is a case where "hazard (possibility)" and "risk (actual exposure)" should be viewed separately. Exceeding the ADI in daily life is rare, and except for specific conditions like PKU, the risk is low if the quantity is monitored.World Health OrganizationIARCU.S. Food and Drug AdministrationCancer Information Center

Vitamin Supplements: Beware of "Excess Harm" Rather Than Deficiency

Fat-soluble vitamins (A, D, E, K) are easily stored in the body. Continuing high-dose supplements without medical advice can pose risks of adverse effects on nerves, liver function, and bleeding tendencies. The original article's blanket statement that "artificial vitamins are harmful" is inaccurate, but the clinical consensus is that "appropriate amounts when necessary" is the basic guideline (this article remains general).

Citric Acid and Aluminum: The Theory Exists, but Discuss "Everyday Amounts"

Citric acid easily forms complexes with aluminum, and there are reports of its involvement in transport across the blood-brain barrier in animal and cell models. However, evidence is lacking on how much this affects human dementia risk at everyday dietary exposure levels. It's important to distinguish between studies discussing possibilities and "risk assessments" concerning real-life quantities.PubMeduknowledge.uky.eduScienceDirect

Reactions on Social Media—The Tug-of-War Between "Alarm" and "Sensationalism"

The headline sparked debate on social media, dividing opinions into three main groups.

• Supporters: Voices advocating for limiting UPF in daily life before mental and cognitive harm occurs. The fact that German foundations and societies issued warnings about UPF in line with World Brain Day also served as "support."hirnstiftung.orgHealthcare in Europe

• Skeptics: Criticism that the IARC's "possibility" and the JECFA/FDA's "risk assessment" considering intake amounts are being confused to incite fear. Many called for the inclusion of international agencies' perspectives on aspartame.World Health OrganizationU.S. Food and Drug Administration

• Pragmatists: Discussions shifted back to overall diet patterns like the Mediterranean diet and focusing on minimally processed foods, arguing against "excessive single-item criticism," given the challenges of human intervention studies (discussion examples: related threads on r/science repeatedly highlighted "limitations of animal studies" and "sustainable lifestyle habits").Reddit
  
  

So, What Should We Do?—A Practical Guide to "Fear Not, Don't Overdo"

1) Don't Make Sweet Drinks and Snacks a "Habit"
Design the frequency, like opting for unsweetened drinks on weekdays and sweets only on weekends.Max Planck Society

2) Read Colors and Labels
Synthetic dyes subject to warning labels in the EU are often used in domestic and international products. Check ingredient lists for "Tartrazine (Yellow 5)" and "Sunset Yellow (Yellow 6)." For sensitive children, consider "observation and substitution."EPHA

3) Manage "Umami" by "Concentration"
The acceptability of MSG is not black and white but depends on quantity and overall diet. On days with a lot of dining out or processed foods, avoid adding "extra umami" snacks to visualize the total amount.EFSA

4) Approach Diet Drinks with an "ADI Sense"
Share awareness of dosage within the family, such as not consuming large amounts regularly and being cautious during pregnancy or for children.World Health OrganizationU.S. Food and Drug Administration

5) Limit Supplements to "Compensating for Deficiencies"
Take appropriate amounts when advised by tests or healthcare providers. Reconsider the "just in case" daily routine of multivitamins.

6) Decide on the "Design" of the Overall Diet First
Focus on unprocessed or minimally processed ingredients, fish, olive oil, nuts, beans, fermented foods, whole grains, fruits, and vegetables—centered around a "Mediterranean-like pattern," with processed foods as side players.Reddit

Conclusion—"Quiet Measures Beyond Headlines" Benefit the Brain

The original article mixed legitimate concerns with exaggerations regarding processed foods and the brain. The potential for excessive sugar and UPF to be a headwind for the brain is being reinforced by both epidemiological and mechanistic research. Meanwhile, MSG and aspartame are managed by national agencies not as "existence = danger" but as "issues of quantity and context." While social media fervor may quickly cool, our daily lives continue. Without excessive fear, quietly redesigning our lifestyles is the shortest route to preventing "brain constipation."hirnstiftung.org##HTML_TAG_500