Fermented kelp, memory and fitness in older adults
What it found
In a 6-week trial in older adults, fermented Laminaria japonica improved some memory test scores and physical fitness measures compared with a placebo.
It also raised antioxidant enzyme activity and lowered markers of oxidative damage.
What they found
Studies in people
Memory and thinking
The fermented kelp group scored higher on the K-MMSE, numerical memory test, Raven test and iconic memory test compared with the placebo group. The placebo group's scores stayed about the same or dropped.
Walking and mobility
Times for the 6-meter walk test got shorter in the fermented kelp group and longer in the placebo group. The Timed Up and Go test also improved in the kelp group, though only the first trial was significantly different between groups.
Antioxidant enzymes
Blood levels of the antioxidant enzymes GPx, GSR and SOD rose in the fermented kelp group and fell in the placebo group. The differences between groups were significant.
Oxidative damage markers
A marker of lipid peroxidation (TBARS) dropped in the kelp group and rose in the placebo group. A marker of DNA damage (8-oxoDG) fell in both groups but much more in the kelp group.
Growth factors
Blood levels of IGF-1 and BDNF increased significantly in the fermented kelp group compared with the placebo group. There was no significant difference between groups in human growth hormone levels.
Body composition
There was no difference in body composition in either group after 6 weeks of supplementation.
What the authors conclude
“The present study highlights the potential widespread application of FST in protecting against the degenerative effects of aging on short-term memory and physical function.”
Also in their conclusions
- They say the study highlights the potential widespread application of fermented Laminaria japonica in protecting against the degenerative effects of aging on short-term memory and physical function.
- They suggest that neuropsychological evaluation indicates fermented Laminaria japonica may provide a protective mechanism against cognitive impairment associated with dementia.
- They propose that improvements in antioxidant activity following supplementation may indicate that the bioactivity of GABA or fucoidans act to provide a defense against progressive degeneration purportedly caused by reactive oxygen species.
How it was done
The authors wanted to see whether fermented Laminaria japonica could be a useful supplement in later life to offset age-related neurodegenerative conditions. They note that oxidative stress is thought to play a role in age-related cognitive decline and dementia.
Sixty moderately active seniors were assigned to take either 1.5 g per day of fermented Laminaria japonica or a placebo for 6 weeks. They were asked not to do any regular exercise. Memory and thinking tests, body composition, fitness tests, antioxidant measures and inflammatory markers were checked before and after.
What it can’t tell you
- The study lasted only 6 weeks, so it cannot show whether any benefits would last longer.
- The participants were moderately active seniors without major diseases, so the results may not apply to other groups.
- The study cannot prove that fermented kelp prevents dementia or other age-related conditions.
Who paid
- Authors work at
- Kyungsung University, Republic of Korea; Seoul National University, Republic of Korea; Marine Bio-Industry Development Center, Republic of Korea
The paper
- Title
- The Effects of Fermented Laminaria japonica on Short-Term Working Memory and Physical Fitness in the Elderly
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Licence
- CC BY. Words in quotation marks are the authors’; the rest is our summary.
- Cite
- Reid SNS, Ryu JK, Kim Y, Jeon BH (2018). The Effects of Fermented Laminaria japonica on Short-Term Working Memory and Physical Fitness in the Elderly. Evidence-based complementary and alternative medicine. doi:10.1155/2018/8109621Free full textPubMed 30008787DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error