Tempeh and Cognitive Function Study

Reference
Hogervorst et al. 2008 High tofu intake memory study
Journal: Dementia and Geriatric Cognitive Disorders (2008)

Study Population

• Participants: ~1,000 elderly Indonesians

• Age: ≥52 years

• Location: Central Java, Indonesia

• Researchers evaluated dietary soy intake and cognitive performance.

The two main foods analyzed were:

• Tempeh (fermented soybean)

• Tofu (non-fermented soybean)

Dietary intake was assessed using food frequency questionnaires.

Cognitive Testing

Cognitive performance was measured using:

• Word recall tests

• Memory recall scores

• General cognitive function testing

These are commonly used tools in dementia research.

Detailed Results

1. Tempeh Intake and Memory

Participants consuming higher amounts of tempeh showed:

• Better immediate memory scores

• Better delayed memory recall

• Better overall cognitive performance

The association remained after adjusting for age and education level.

Typical intake levels associated with benefit:

• approximately 50–100 g tempeh daily

Researchers suggested fermented soy might provide neuroprotective nutrients.

2. Tofu Intake and Memory

Interestingly, high tofu intake was associated with worse memory performance.

Findings included:

• lower memory recall scores

• poorer cognitive test results

The association was particularly noticeable in:

• older participants (>68 years).

3. Combined Findings

Participants who consumed more tempeh but less tofu had the best cognitive outcomes.

The authors suggested this might be due to differences in:

• fermentation

• micronutrient content

• bioactive compounds.

Possible Biological Mechanisms

Researchers proposed several explanations.

1. Vitamin B12 Production

Tempeh fermentation can produce B12-like compounds, which may help maintain:

• nerve function

• cognitive performance.

2. Increased Antioxidants

Fermentation increases:

• polyphenols

• antioxidant activity.

These may help protect brain cells from oxidative stress.

3. Improved Protein Digestion

Fermentation breaks soy proteins into:

• smaller peptides

• amino acids

This may enhance nutrient absorption.

4. Gut–Brain Axis Effects

Fermented foods can influence:

• gut microbiota

• immune signaling

• inflammation

All of which may affect brain health.

Important Note

The study was observational, meaning it shows association rather than proof of causation.

However, it provides important evidence suggesting fermented soy foods may support cognitive health.

Simple Take-Home Message

Compared with non-fermented soy foods like tofu:

Fermented soy (tempeh) intake was associated with better memory performance and cognitive scores in elderly adults.