Knowledge base

Algal omega-3 EPA and DHA

Microalgae are a non-fish source of the long-chain omega-3 fats DHA and EPA. Adults following vegetarian and vegan diets take in less EPA and DHA and have lower blood levels than meat-eaters, and randomised trials show that algal-derived DHA supplements raise blood DHA and the omega-3 index in vegan, vegetarian and omnivorous adults, with algal-oil capsules delivering DHA as well as cooked salmon. Algal DHA lowered blood triglycerides in a meta-analysis of small trials, but no trials have tested algal omega-3 against hard health outcomes in vegans, and large trials of mostly fish-oil omega-3 found little or no effect on mortality or cardiovascular events.

• Longevity
• Vegan

6 claims

Calcium

Adults following a vegan diet eat substantially less calcium than other diet groups and, in large observational studies, have lower bone mineral density and higher fracture rates, especially hip fractures. In adults over 50, raising calcium intake from food or supplements produces small, non-progressive gains in bone mineral density; dietary calcium intake is not associated with fracture risk, and trial evidence on fractures is mixed, with combined calcium and vitamin D looking more promising than vitamin D alone. Large trials and meta-analyses link calcium supplements with more kidney stones and possibly more heart attacks.

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5 claims

Choline

Choline is an essential nutrient: in controlled feeding studies most adults deprived of dietary choline developed fatty liver or muscle damage that reversed when choline was restored. Surveys suggest most adults and most pregnant women eat less than the adequate intake, and vegetarian and vegan diets tend to supply less because choline is concentrated in animal foods. Evidence that extra choline in pregnancy improves child development is insufficient, cohort links between higher intake and better cognition are observational, and very high intakes have known side effects.

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6 claims

Daily food targets

Daily food-group targets in dietary guidance rest mainly on dose-response meta-analyses of large prospective cohorts. In adults, eating more fruit and vegetables, whole grains, dietary fibre and nuts each day is associated with lower all-cause mortality and a lower risk of cardiovascular disease, with the lowest mortality seen at about five servings of fruit and vegetables and about 25 to 29 g of fibre a day, while more red and processed meat is associated with higher risk. The WHO sets population targets of at least 400 g of fruit and vegetables and at least 25 g of fibre a day for everyone older than 10. Because the evidence is mostly observational, the strongest grade here is moderate.

• Longevity
• Vegan

5 claims

Fermented foods and polyphenols

Randomised trials in healthy adults link eating fermented foods with modest improvements in bowel habits and gut comfort, and one small trial found a fermented-food diet raised gut microbiota diversity and lowered inflammatory markers; the certainty of this evidence is mostly low. Cohort studies associate fermented milks, cheese and chocolate with lower mortality. Among polyphenols, cocoa flavanols have moderate-certainty trial evidence for a small short-term fall in blood pressure, and cohort studies associate flavan-3-ol intake with better cardiometabolic outcomes. Concentrated green tea extract supplements are the main safety exception, with case reports of liver injury.

• Longevity
• Vegan

6 claims

Iodine

Iodine is needed to make thyroid hormones, which regulate growth, development and metabolism, and low intake early in life impairs cognition and growth. Adults following vegan diets have the lowest iodine intake and status of any dietary group studied, especially where salt is not routinely iodised. Population salt iodisation programmes are linked with adequate iodine status, while trials of iodine supplements in pregnancy in mildly to moderately deficient settings show better maternal iodine status but no clear infant benefit. Too much iodine, including from some seaweeds such as kelp, is also linked with thyroid dysfunction.

• Energy
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• Vegan

5 claims

Iron

Adults following vegetarian or vegan diets have lower iron stores (serum ferritin) than meat-eaters, because plant foods supply only non-haem iron, which is less well absorbed; mean haemoglobin is similar across diet patterns, while the evidence on anaemia prevalence is mixed. Eating ascorbate-rich fruit with meals probably raises ferritin and haemoglobin modestly. Adding vitamin C to oral iron supplements adds little, and iron supplements raise iron status in menstruating women at the cost of more gastrointestinal side effects.

• Energy
• Vegan

5 claims

Legumes, whole grains, nuts

Randomised trials show that eating tree nuts or dietary pulses (beans, chickpeas, lentils, peas) lowers LDL cholesterol in adults, and large meta-analyses of cohort studies link higher whole grain and nut intake with lower cardiovascular disease and all-cause mortality. Cohort evidence for legumes and cardiovascular outcomes is weaker and graded low to very low by its authors. A modelling study that combines these meta-analyses estimates that eating more legumes, whole grains and nuts accounts for much of the predicted gain in life expectancy from a shift away from a typical Western diet, but its figures are population estimates under stated assumptions.

• Longevity
• Vegan

6 claims

Protein and leucine

Expert groups conclude that older adults need more dietary protein than younger adults, and many older adults eat less than that. In randomised trials, eating more protein gave small extra gains in lean mass and leg strength in healthy adults doing resistance exercise, with little further gain above about 1.6 g per kilogram of body weight a day. Leucine supplements raised muscle protein synthesis in older adults without a measurable gain in lean mass. Plant and animal protein sources produced similar changes in absolute lean mass and strength, although many plant proteins carry less leucine, lysine or methionine. In healthy adults, higher-protein diets did not change kidney function in trials.

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• Vegan

5 claims

Selenium

Selenium is an essential trace element found mostly in animal foods and in Brazil nuts, and a small 2025 trial found lower selenium intake in adults following a vegan diet than in omnivores, with Brazil nut butter raising selenium status as well as a supplement did. Large, well-conducted randomised trials found that selenium supplements did not lower cancer or cardiovascular risk in adults, and pooled trials suggest a small increase in type 2 diabetes risk. In people with Hashimoto thyroiditis, trials found lower thyroid antibody and TSH levels with selenium. Intakes above the EFSA upper level are possible with high-dose supplements or regular Brazil nut eating.

• Longevity
• Vegan

6 claims

Time-restricted eating

Time-restricted eating limits daily food intake to a set window, typically 4 to 10 hours in trials. In adults, mostly with overweight or obesity, it reduces body weight compared with an unrestricted usual diet, but randomised trials and meta-analyses mostly find no clear extra benefit over ordinary daily calorie restriction of the same intensity. In adults with prediabetes or type 2 diabetes it modestly lowered fasting blood glucose but not HbA1c. Trials report no overall excess of adverse events, though one meta-analysis found more hunger than with calorie-matched diets, and most trials are short.

5 claims

Vitamin B12

Plant foods are not a reliable source of vitamin B12, so adults on an unsupplemented vegan diet have lower B12 status and more functional deficiency than omnivores, while supplement users show better biomarker levels. Long-term deficiency affects red blood cell production and the nervous system and is most serious in infants. In adults who are not deficient, randomised trials found no benefit of extra B12 for cognition or mood.

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6 claims

Vitamin D

In Australia and New Zealand most vitamin D comes from sunlight rather than food, so low status is most common in people who get little sun, such as housebound or institutionalised older adults and people with dark skin. In randomised trials, vitamin D on its own did not reduce fractures or falls or meaningfully change bone density in adults not selected for deficiency, while vitamin D combined with calcium was linked to a small reduction in fractures in older adults. Trials also found a small overall reduction in acute respiratory infections. Vitamin D3 raised blood levels more than D2 in trials, mainly at large infrequent doses, and people on plant-based diets tend to have lower vitamin D intake and status.

• Longevity
• Vegan

6 claims

Vitamin K2

Vitamin K2 (menaquinones, including MK-7 from the fermented soybean food natto) supports the carboxylation of vitamin K-dependent proteins such as osteocalcin, and supplementation trials consistently shift these markers. Effects on outcomes that matter are less certain: pooled trials in postmenopausal women show small lumbar spine bone density gains that shrink when higher-risk-of-bias trials are removed, fracture results are inconsistent, and effects on artery calcification and stiffness are mixed. MK-7 supplements can weaken the effect of vitamin K antagonist anticoagulants even at low intakes.

• Longevity
• Vegan

6 claims

Whole-food plant pattern

Eating patterns built mostly on whole plant foods (vegetables, fruits, whole grains, legumes, nuts) are linked in large cohort studies with lower cardiovascular, type 2 diabetes and all-cause mortality risk, and randomised trials show vegetarian and vegan diets lower LDL cholesterol. The quality of the plant foods matters: plant patterns heavy in refined and ultra-processed plant foods are linked with higher, not lower, risk.

• Longevity
• Vegan

5 claims

Zinc

Zinc is an essential trace mineral. Populations following vegetarian and vegan diets tend to have lower zinc intakes, and pooled studies also show lower serum zinc, largely because phytate in whole grains, legumes and seeds reduces zinc absorption; food preparation such as soaking, sprouting, fermenting and leavening reduces phytate. Trials of zinc taken during a common cold suggest shorter colds with more minor side effects, at low certainty. Excessive zinc intake over time can disrupt copper metabolism.

• Vegan

5 claims

Cardiorespiratory fitness

Cardiorespiratory fitness, usually measured as maximal aerobic capacity in an exercise test, is one of the most consistent predictors of health in large cohort studies: adults with higher fitness have lower rates of death from all causes and of cardiovascular events, with a dose-response pattern per 1-MET difference. Higher fitness is also associated with lower rates of cancer death, type 2 diabetes and depression, though that evidence is thinner. Controlled trials show that endurance and interval training both raise VO2max in healthy young to middle-aged adults. The fitness-outcome evidence is observational, so it shows association rather than proof that raising fitness causes the lower risk.

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6 claims

Daily steps

Large pooled analyses of prospective cohorts with device-measured steps find that adults who take more steps a day have a progressively lower risk of death and of cardiovascular disease, with associations for type 2 diabetes, dementia and depressive symptoms resting on fewer studies. The lower risk levels off below the popular 10 000 step figure, at a point that differs by age, and associations appear from a few thousand steps above the least active level. All the evidence is observational, so residual confounding and reverse causation remain possible.

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5 claims

Mobility and balance

In older adults living in the community, exercise programmes built mainly on balance and functional exercises reduce falls, with high-certainty evidence from a Cochrane review of randomised trials, and exercise may also modestly improve balance measures and reduce fear of falling. Regular stretching increases joint range of motion in healthy adults, and strength training appears to give similar gains, but this evidence is low certainty and no trials have tested flexibility exercise alone for falls. Tai chi for falls is covered in the qigong-and-tai-chi topic.

• Longevity
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5 claims

Protein with resistance training on plant diets

Meta-analyses of randomised trials found that soy protein supports resistance-training gains in lean mass and strength much like animal protein, and that strength gains do not differ by protein source. Pooled trials show a small muscle-mass edge for animal protein over non-soy plant proteins, mostly in younger adults, while small training trials of high-protein vegan diets found comparable gains. Acute studies show plant proteins stimulate less muscle protein synthesis gram for gram; anabolic resistance in older adults is a separate topic.

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5 claims

Strength training

In older adults, randomised trials show that progressive resistance training increases muscle strength substantially and improves some measures of physical function. In adults generally, trials link resistance training with modestly lower resting blood pressure and fewer depressive and anxiety symptoms, and cohort studies associate muscle-strengthening activities with a lower risk of death and major non-communicable diseases, with the largest association at about 30-60 minutes a week and unclear added benefit beyond that.

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• Strength

5 claims

Zone 2 vs intervals

Both steady moderate-intensity (continuous or "Zone 2") training and high-intensity interval training raise aerobic fitness substantially in trials, with interval training producing somewhat larger gains in maximal oxygen uptake in healthy adults and in adults living with lifestyle-related cardiometabolic conditions. For body fat the two approaches performed similarly in overweight adults, with interval training taking less time. A 2025 narrative review found no trial evidence that Zone 2 is the optimal intensity for mitochondrial or fat-burning capacity in the general population. In supervised cardiac rehabilitation, serious cardiac events were rare with both kinds of training.

• Energy
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5 claims

Bedroom temperature

Real-world and laboratory studies consistently find that warmer nights and hot bedrooms are linked with shorter, less efficient sleep, with older adults among the most affected; one home-monitoring study of older adults found sleep was most efficient between about 20 and 25 °C. Children who sleep in rooms that are too hot or too cold also show poorer sleep, and paediatric guidance lists avoiding overheating as part of a safe infant sleep environment. No claim reaches moderate or high certainty because the evidence is mostly observational or from small laboratory studies, and the systematic review did not pool results.

• Sleep

6 claims

CBT-I for insomnia

Cognitive behavioural therapy for insomnia (CBT-I) is a structured, multicomponent programme combining cognitive work around sleep with behavioural methods such as stimulus control and sleep restriction. In randomised trials of adults living with long-term insomnia symptoms it shortened time to fall asleep and time awake at night, including when delivered over the internet and alongside other health conditions, and major clinical guidelines recommend it as the first approach. Sleep restriction can bring temporary daytime sleepiness in the first weeks.

• Mind
• Sleep

5 claims

Light exposure and circadian rhythm

Light is the main signal that sets the body clock: in adults, evening and night light reduces the evening rise in melatonin and can increase alertness before bed, while brighter daytime light is associated with better sleep, mood and earlier body-clock timing. Large UK cohort studies link bright days and dark nights with lower all-cause mortality, and a meta-analysis found bright light sessions improved sleep problems with small to medium effects. Most of the population-level evidence is observational, so only the melatonin effect reaches moderate certainty.

• Longevity
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• Sleep

4 claims

Sleep duration and regularity

Expert panels describe 7 to 9 hours a night as appropriate for healthy adults (7 to 8 hours for older adults). In population studies both habitually short and habitually long sleep are associated with higher mortality, and short sleep with obesity and type 2 diabetes, but this evidence is observational. More regular sleep timing is associated with better health and lower mortality in cohorts, and experiments show that acute sleep loss impairs attention.

• Longevity
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• Sleep

5 claims

Exercise for mood

Randomised trials across adult populations show that physical activity programmes improve symptom scores for low mood, anxiety and psychological distress, with consistent medium effects. Trials in adults whose depressive symptoms meet clinical cut-offs point the same way, though most were at risk of bias. Higher-intensity programmes were linked to larger changes, a single bout lifts mood in the short term, and active adults in cohort studies have lower risk of depression.

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6 claims

Mindfulness programmes

Structured mindfulness-based programmes, mostly group courses of around 8 weeks, produce small to moderate improvements in anxiety, low mood, distress and well-being scores in adults compared with taking no action, though effects vary by setting and they have not been shown to beat other active options such as exercise or other behavioural programmes. Trials and newer network meta-analyses suggest a modest benefit for self-reported sleep quality, including in older adults, with small effects for digital programmes. A minority of practitioners report unwanted effects such as anxiety or low mood, although in one digital programme trial such experiences were about as common in participants who did not meditate.

• Mind
• Sleep

4 claims

Purpose in life

A sense of purpose in life, meaning having goals and a feeling that life is meaningful, is consistently associated in large cohort meta-analyses with lower risk of earlier death and of dementia and with fewer depressive symptoms, though these are observational associations that may partly reflect health behaviours, illness and mood. Randomised trials show that structured programmes, including brief and non-professional ones, can raise sense of meaning, with the most consistent evidence in adults living with cancer; whether raising purpose changes health outcomes has not been shown in trials.

• Longevity
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5 claims

Slow-paced breathing

Slow-paced breathing, usually around six breaths a minute, consistently raises heart rate variability linked to parasympathetic activity. Trials of breathwork that is mostly slow-paced, and of heart rate variability biofeedback, show small to moderate reductions in self-reported stress, anxiety and low mood, but these trials carry risk of bias and vary widely. Few harms have been reported, though few trials looked for them.

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5 claims

Social connection

Large meta-analyses of cohort studies link stronger social relationships with longer survival and link loneliness and social isolation with higher risks of early death, coronary heart disease, stroke and dementia, with associations comparable in size to well-established lifestyle risk factors. This evidence is observational, so it shows association rather than cause. Trials of interventions to reduce loneliness, particularly psychological approaches, show small to moderate benefits, but reviewers rate the certainty of that evidence low.

• Longevity
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5 claims

Creatine

Creatine is a compound found mainly in meat and fish that helps recycle cellular energy in muscle and brain. Meta-analyses of randomised trials found that creatine taken alongside resistance training increased strength in adults and increased lean tissue mass and strength in older adults. Trials suggest a small benefit for memory, most clearly in older adults, but results are inconsistent. People following vegetarian diets start with lower muscle creatine and may respond more in muscle. Trials of up to about a year found a rise in serum creatinine without changes in kidney filtration in healthy people.

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• Vegan

5 claims

Magnesium (sleep)

Magnesium supplements are widely used to support sleep, but randomised trials in adults give inconsistent results: small trials in older adults found people fell asleep somewhat sooner, while a 2026 systematic review of 12 trials rated the evidence low to very low certainty. Observational studies link better magnesium status with better sleep quality, which does not show cause and effect. The only claim graded moderate concerns safety: high supplemental doses commonly cause loose stools, and authorities set an adult upper level for magnesium from supplements; none of the sleep-benefit claims reach moderate because the trials are few, small, heterogeneous and at risk of bias.

• Sleep

5 claims

Melatonin (sleep)

Melatonin is a hormone that helps time the body clock, and melatonin supplements are most often made synthetically. Randomised trials show the clearest benefit for jet lag in air travellers crossing five or more time zones. For adults with long-standing sleep difficulties the effects are small and inconsistent: an older meta-analysis found sleep onset about 7 minutes faster, a 2022 meta-analysis found no significant effect in adults, and a 2017 sleep-medicine guideline suggests against it for chronic insomnia. Short-term use appears to be well tolerated in trials, long-term safety data are lacking, and the dose in over-the-counter products often differs from the label.

• Sleep
• Vegan

5 claims

Abhyanga (self oil massage)

Abhyanga is the Ayurvedic practice of oil massage, described in classical texts as part of the daily regimen (dinacharya) that nourishes the tissues, gives strength and eases stiffness. Clinical research on it is thin: one small randomised trial found that adding daily self-massage with sesame oil to stretching improved hamstring flexibility in young men more than stretching alone, a 20-person uncontrolled pilot reported lower self-rated stress and heart rate after a single session, and a 2026 review judged the sleep trials small, short and hard to blind. No claim here is graded moderate or high because the evidence is a handful of small, unblinded or uncontrolled studies with no systematic review specific to abhyanga. Skin reactions to Ayurvedic massage oils are reported in case reports.

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5 claims

Acupuncture for chronic pain

Acupuncture comes from traditional Chinese medicine, which explains it as restoring the flow of qi along meridians. In individual patient data meta-analyses of adults with chronic back, neck, osteoarthritis, headache and shoulder pain, acupuncture lowered pain scores clearly against no acupuncture and modestly against sham, with most of the effect still present at one year, so it may help people living well with chronic pain. Serious adverse events are rare but are linked to non-sterile needles and improper technique.

• Recovery

5 claims

Acupuncture for migraine prevention

Acupuncture originated in traditional Chinese medicine, where points are chosen by meridian diagnosis. In adults with episodic migraine, a 2016 Cochrane review of 22 trials found that adding a course of acupuncture to usual care more than doubled the share of people whose headache frequency halved, with a smaller advantage over sham needling and results at least similar to preventive drugs with fewer side-effect dropouts. A 2026 review rates the advantage over sham as low certainty, and trials longer than a year are lacking.

• Recovery

5 claims

Agni and meal timing

Ayurveda describes Agni as the digestive fire whose strength varies with the time of day, and holds that the main meal belongs at midday, with a light dinner well before sleep and regular eating hours. Studies of the testable parts find that shifting more of the day's calories earlier brings slightly greater weight loss, that the same meal raises energy expenditure more in the morning than in the evening, that a late dinner worsens overnight glucose handling, and that early-window time-restricted eating lowers fasting glucose. No claim reaches moderate certainty, because the evidence comes from few small short trials, trials mostly at high risk of bias, or subgroup analyses.

• Energy

6 claims

Dinacharya daily rhythm

Dinacharya is the Ayurvedic daily routine: rising before sunrise, taking the main meal at midday, eating a light dinner well before sleep and keeping regular hours. Studies of the testable parts find that more daytime outdoor light goes with easier waking and fewer insomnia symptoms, that earlier calorie distribution and earlier eating windows bring small metabolic and weight benefits, that a late dinner worsens overnight glucose handling, and that regular sleep timing is linked to lower mortality. No claim reaches moderate certainty, because the evidence comes from small short trials, trials at high risk of bias or observational cohorts.

• Energy
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• Sleep

5 claims

Fasting (langhana, religious fasts)

Fasting is part of many traditions: Ayurveda treats langhana (lightening therapy, of which fasting is one form) as a core way to restore balance, and Islam, Christianity, Hinduism, Judaism, Buddhism and Jainism keep religious fasts. Observational studies of Ramadan fasting show small reductions in body weight, waist size and blood pressure that tend to reverse after the month, and randomised trials of intermittent fasting diets show weight and cardiometabolic results broadly similar to continuous calorie restriction. People with diabetes and other medical conditions face specific risks when fasting, and guidelines call for individual guidance.

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5 claims

Loving-kindness meditation

Loving-kindness (metta) meditation, a Buddhist practice of wishing well to oneself and others, has been tested in many small randomised trials. Meta-analyses find small to medium gains in positive emotions, compassion and self-compassion, and fewer low-mood symptoms, compared with doing nothing, but no clear advantage over other active activities. No claim reaches moderate or high certainty because the trials are small, mostly compared against wait-list or passive controls, and of low to moderate methodological quality.

• Mind

5 claims

Oil pulling

Oil pulling is an Ayurvedic practice of swishing an edible oil, often sesame or coconut, around the mouth and spitting it out. Short trials suggest it may modestly improve gum scores and salivary bacteria counts, but it does not clearly reduce plaque more than usual care and is less effective than chlorhexidine mouthwash; the tradition's wider claim of whole-body detoxification is untested. No claim reaches moderate or high certainty because the trials are small, short and at high risk of bias, and the systematic reviews disagree. Rare case reports describe lipoid pneumonia from aspirated oil, and reviews describe the practice as an addition to brushing, not a replacement.

6 claims

Prakriti (dosha) assessment

Ayurveda holds that each person has a lifelong constitution, Prakriti, made up of a particular mix of the three doshas Vata, Pitta and Kapha, and uses it as the basis of individualised care. Reviews of the research count dozens of Prakriti assessment questionnaires, algorithms and devices, of which only a minority have had any reliability or validity testing, and agreement between assessors or between repeat questionnaires on the final Prakriti type has often been fair to poor. A few small studies, mainly in Indian adults, report genetic and biochemical differences between people classified as extreme Vata, Pitta or Kapha types, but these findings are early and not established. Prakriti remains a research construct rather than a validated measure.

• Mind

4 claims

Pranayama at about six breaths per minute

Pranayama is the yoga practice of breath regulation, which the tradition explains as extending prana, vital energy. Slow forms of pranayama and other slow breathing at around six to ten breaths a minute have been tested in trials: meta-analyses of randomised trials in adults with high or high-normal blood pressure show modest falls in blood pressure and heart rate over weeks of practice, though the trials vary and carry risk of bias. Slow yogic breathing appears to act on cardiovascular and autonomic measures where fast techniques do not. Heart rate variability, stress and mood effects of slow breathing are covered in the slow-breathing entry.

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5 claims

Qigong and tai chi

Tai chi and qigong are slow, meditative movement practices from China. In community-dwelling older adults, tai chi lowers the number of people who fall (moderate certainty overall). Smaller, lower-quality bodies of trials suggest benefits for blood pressure in adults with hypertension, depressive symptoms in middle-aged and older adults, and sleep quality in older adults (low certainty). Traditional Chinese medicine frames qigong as cultivating qi; that frame is not graded. Both practices appear safe.

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5 claims

Ritucharya (seasonal routine, S. Hemisphere)

Ritucharya is the Ayurvedic seasonal regimen: the classics divide the year into six seasons and set out a diet and lifestyle for each, holding that people who follow the regimen suited to each season gain strength and complexion. The classical season dates follow the Indian calendar, so in the Southern Hemisphere the seasons fall in opposite months, and Ayurvedic commentators hold that the regimen should follow the season's actual qualities rather than fixed dates. Studies of the testable premise, that the body changes with the seasons, find seasonal patterns in immune gene expression that are inverted between Europe and Oceania, higher blood pressure in colder weather worldwide, and season as a major determinant of vitamin D status in Australian adults. Only the blood pressure claim reaches moderate certainty, and no trial has tested following Ritucharya itself.

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5 claims

Tongue scraping

Tongue scraping is a daily practice in Ayurveda, which links it to oral hygiene and digestion. Trials in adults show that cleaning the tongue reduces tongue coating and breath odour compounds in the short term, but evidence for longer-term benefit in people with bad breath is very uncertain. Small studies suggest possible effects on taste, on respiratory function in older adults in care and on self-reported digestion. No claim reaches moderate certainty because the trials are few, small, short and mostly measure surrogate outcomes.

5 claims

Yoga for sleep

Randomised trials pooled in several meta-analyses found that yoga programmes improve self-reported sleep quality in women with sleep problems and increase diary-recorded sleep time in adults with insomnia, with no serious adverse events reported. Effects were smaller or uncertain in people with breast cancer and around menopause, walking outperformed yoga for sleep disturbance in cancer trials, and cognitive behavioural therapy for insomnia keeps the strongest evidence among non-drug approaches. Most trials were small, unblinded and relied on self-report, which limits certainty.

• Sleep

5 claims

Yoga nidra

Yoga nidra is a guided, lying-down relaxation practice that the yoga tradition treats as pratyahara, withdrawal of attention from the senses; its modern form was standardised at the Bihar School of Yoga in 1976. Recent meta-analyses report lower stress, anxiety, pain and blood pressure and possibly better sleep after practice, but the trials are small, mostly at high risk of bias and concentrated in a few settings, and the reviewers expect the effect sizes are inflated. No claim reaches moderate certainty because every pooled estimate rests on few, small, poorly blinded studies with inconsistent protocols.

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5 claims

Ashwagandha

Ashwagandha (Withania somnifera) is a leading rasayana, or rejuvenating tonic, in Ayurveda, traditionally used to build strength and resilience to stress. Meta-analyses of small randomised trials suggest standardised extracts may modestly improve sleep and lower self-reported stress and anxiety over several weeks, but no claim reaches moderate certainty because the trials are few, small, use different extracts and disagree in effect size. Rare cases of liver injury have been reported, several European authorities and the Australian TGA have reviewed its safety, and it is advised against in pregnancy and breastfeeding.

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4 claims

Culinary spices

Culinary spices such as cinnamon, ginger and garlic have long histories in folk and traditional medicine, and several have been tested in randomised trials, mostly as concentrated supplements rather than as food. Trials suggest small improvements in blood glucose markers with cinnamon in adults with type 2 diabetes, less nausea with ginger in pregnancy and lower blood pressure with garlic in adults with high blood pressure, and a large Chinese cohort linked regular spicy food with lower mortality. None of these findings reaches moderate certainty, because the trials are small, varied in product and dose, and highly heterogeneous, and the mortality evidence is observational. Spices in food amounts are generally regarded as safe; heavy use of cassia cinnamon can bring coumarin intake up to the tolerable daily intake.

• Vegan

6 claims

Traditional products to avoid

Regulators and researchers have documented three recurring safety problems with some traditional remedies: toxic metal content in a share of Ayurvedic medicines, especially rasa shastra preparations that deliberately include metals; herbs containing aristolochic acids, which are linked to kidney damage and urinary tract cancers; and undeclared pharmaceutical drugs found in some Chinese herbal and supplement products. Some traditional products also contain animal-derived ingredients such as bear bile.

• Vegan

5 claims

Triphala

Triphala is an Ayurvedic blend of three dried fruits (amalaki, bibhitaki and haritaki) that the tradition uses as a digestive and rejuvenative rasayana. Small randomised trials suggest a triphala mouthrinse lowers plaque and gum inflammation scores about as much as chlorhexidine, and give very uncertain signals for blood lipids and body weight. No claim reaches moderate certainty because the trials are few, small, heterogeneous and use varied formulations; product quality is the main safety concern.

• Longevity

5 claims

Turmeric and curcumin

Turmeric root has a long history in Ayurvedic, Chinese and other traditional medicine systems, and European herbal regulators register it as a traditional remedy for mild digestive discomfort on the basis of long-standing use. In trials of adults with knee osteoarthritis, turmeric extracts and curcumin reduced pain and stiffness scores compared with placebo and were tolerated about as well as placebo over weeks to months. No claim reaches moderate certainty because a 2026 critical review rated the systematic reviews behind the joint findings as of extremely low methodological quality, with most outcomes graded low or very low. Rare but potentially severe liver injury has been reported with concentrated turmeric and curcumin supplements, especially high-bioavailability or black-pepper-enhanced products.

• Recovery
• Vegan

4 claims

Stroke (vegan-specific risk)

In the UK EPIC-Oxford cohort, vegetarians (including vegans) had higher rates of total and haemorrhagic stroke than meat eaters, but a meta-analysis of prospective cohorts found no clear overall association between vegetarian diets and stroke, and Taiwanese cohorts found lower stroke risk in vegetarians. Vegan-specific estimates rest on few cases and are imprecise. Proposed explanations, such as low vitamin B12 with raised homocysteine or low LDL cholesterol, remain untested hypotheses. No claim reaches moderate certainty because all of the evidence is observational, the cohorts disagree with one another, and the vegan subgroups are small.

• Longevity
• Vegan

4 claims