When people travel to high altitudes, their brains don’t get as much oxygen, which can make them feel moody and have trouble thinking clearly. Researchers wanted to know if taking special supplements made from fiber and plant compounds could help protect the brain during high-altitude exposure. They tested 13 young adults in a special chamber that simulated being at 14,100 feet elevation. While the supplements didn’t improve thinking skills, they did seem to reduce anger that normally happens at high altitudes. However, the study was small and short, so more research is needed before we know if these supplements really work.

The Quick Take

  • What they studied: Whether taking supplements containing fiber and plant nutrients could protect mood and thinking ability when the body doesn’t get enough oxygen at high altitudes
  • Who participated: 13 healthy young adults (average age 21 years old) who participated in three separate 2-week phases of the study
  • Key finding: The supplements did not improve thinking skills or memory at high altitude, but they may have reduced anger that normally occurs when oxygen levels are low. High altitude still caused mood problems and thinking difficulties regardless of the supplement.
  • What it means for you: If you’re planning a high-altitude trip, these particular supplements probably won’t prevent the brain fog and mood changes you might experience. However, the small study size means we can’t be completely certain—larger studies are needed to confirm these results.

The Research Details

This was a carefully controlled experiment where the same 13 people participated in three different 2-week periods. During each period, they either took the supplement or a placebo (fake pill with no active ingredients). At the end of each period, they spent 36 hours in a special chamber that simulated either sea level (1,640 feet) or high altitude (14,100 feet). The researchers tested their mood and thinking ability using computer-based tests each morning, evening, and after leaving the chamber.

This type of study design is considered very reliable because each person serves as their own comparison—researchers can see how the same person responds with and without the supplement. The use of a placebo helps ensure that any changes aren’t just because people expect the supplement to work.

The study carefully controlled the environment by using a hypobaric chamber, which removes oxygen from the air to simulate high altitude without people actually traveling. This allows researchers to study the effects in a safe, controlled setting.

This research approach is important because it allows scientists to isolate the specific effects of the supplement from other factors that happen during real mountain climbing, like physical exertion, temperature changes, and dehydration. By testing people in a controlled chamber, researchers can be more confident that any changes in mood or thinking are due to the supplement and altitude, not other variables.

This study has both strengths and weaknesses. The strength is that it used a randomized, placebo-controlled crossover design, which is considered a gold standard in nutrition research. However, the study only included 13 people, which is a very small sample size. This means the results might not apply to larger, more diverse populations. Additionally, people only took the supplement for 2 weeks, which may not be enough time to see significant effects. The study also had short washout periods between phases, meaning the supplement’s effects from one phase might have carried over to the next.

What the Results Show

When people were exposed to simulated high altitude (4,300 meters or 14,100 feet), they experienced significant mood and thinking changes regardless of whether they took the supplement or placebo. These changes included feeling more sad, tense, tired, and depressed, while also feeling less energetic and having less self-control.

The supplement did not prevent these altitude-related thinking problems. Tests of memory, attention, and other mental skills showed similar difficulties in both the supplement and placebo groups at high altitude.

However, there was one interesting finding: anger increased significantly at high altitude when people took the placebo, but this anger increase was reduced when people took the supplement. This suggests the supplement may have some protective effect against altitude-induced anger, though this was a secondary finding and needs confirmation in larger studies.

At low altitude, both groups performed similarly on all tests, showing that the supplement didn’t provide any advantage when oxygen was plentiful.

Confusion was actually higher in the supplement group at high altitude compared to the placebo group at low altitude, which was unexpected. This could suggest the supplement might have had a negative effect on mental clarity, though this finding was small and could be due to chance. Additionally, people made more mistakes on vigilance tests (tests measuring attention) at low altitude compared to high altitude, which was surprising and contradicts what researchers expected.

Previous research has shown that high altitude causes mood problems and thinking difficulties due to reduced oxygen. This study confirms those findings. However, the idea that fiber and plant-based supplements could protect the brain at altitude is relatively new. This study suggests that while these supplements might help with anger, they don’t provide the broader cognitive protection that researchers hoped for. The results align with other recent research showing that many supplements have limited effects on brain function during stress.

The study had several important limitations. First, only 13 people participated, which is very small. This means the results might not apply to other people, especially those of different ages, fitness levels, or backgrounds. Second, people only took the supplement for 2 weeks, which may not be enough time for the body to fully benefit. Third, the washout periods between study phases were short, so effects from one phase might have influenced the next. Fourth, all participants were young and healthy, so results might be different for older adults or people with health conditions. Finally, the study only measured short-term effects during the chamber stay, not long-term benefits.

The Bottom Line

Based on this research, we cannot recommend these specific supplements for preventing altitude-related thinking problems (low confidence level). The evidence suggests they may slightly reduce anger at high altitude, but this finding needs confirmation in larger studies (very low confidence level). If you’re planning high-altitude travel, focus on proven strategies like gradual acclimatization, staying hydrated, and getting adequate sleep instead of relying on these supplements.

Mountain climbers and people planning high-altitude trips might be interested in this research, though the findings don’t yet support using these supplements. Athletes training at altitude, pilots, and people with jobs at high elevation might also want to follow future research on this topic. People with mood disorders or cognitive concerns should not use these supplements as a treatment without consulting their doctor. This research is not relevant for people living at sea level.

If these supplements were to work, you would likely notice effects within days to weeks, not months. In this study, researchers tested people after just 2 weeks of supplementation. However, the lack of clear benefits in this timeframe suggests that if these supplements do help, the effects are likely small and would require larger studies to detect.

Want to Apply This Research?

  • If using a health app while traveling to high altitude, track daily mood ratings (1-10 scale), energy levels, and any anger or irritability. Also note cognitive symptoms like difficulty concentrating, memory problems, or confusion. Compare these ratings before, during, and after altitude exposure.
  • Rather than relying on supplements, use your app to track and implement proven altitude adaptation strategies: drink 3-4 liters of water daily, sleep 8+ hours, avoid alcohol, and gradually increase altitude exposure. Log these behaviors and correlate them with mood and thinking improvements.
  • Create a baseline of your normal mood and cognitive function at sea level. When traveling to altitude, use your app to log daily mood, energy, mental clarity, and any anger or irritability. Continue tracking for 2-3 weeks after returning to sea level to see how quickly you recover. This personal data is more useful than general supplement recommendations.

This research is preliminary and based on a very small study of 13 young, healthy adults. The findings do not constitute medical advice. Before taking any supplements, especially if you have existing health conditions, take medications, or are pregnant or breastfeeding, consult with your healthcare provider. If you experience severe symptoms at high altitude such as difficulty breathing, severe headache, or confusion, seek immediate medical attention. This study should not be used to replace established medical treatments or altitude acclimatization protocols recommended by healthcare professionals.