M-Smart

Pooled across 12 randomized trials in 615 adults, mulberry leaf and mulberry leaf extract were associated with lower fasting glucose, glycated hemoglobin and fasting insulin. This is the strongest current synthesis for the botanical, and the authors report meaningful heterogeneity between trials.

Cui W et al. — Food & Function

A randomized bioequivalence trial found the postprandial glucose-lowering effect of mulberry extract is largely attributable to its 1-deoxynojirimycin content, with other extract components contributing modestly. This is the key citation for why standardizing to DNJ is the meaningful specification.

Hoogenraad AR et al. — The Journal of Nutrition

Timing of intake changes how well the extract works: taken in the evening, acute mulberry leaf extract improved the post-meal glucose response in healthy adults, a larger effect than the same dose earlier in the day. Practical potentiation finding -- it points to dosing the ingredient close to the meal that matters most.

Takahashi M et al. — European Journal of Clinical Nutrition

Mulberry leaf extract inhibited alpha-amylase and alpha-glucosidase in vitro and lowered the post-meal glucose rise in a randomized crossover trial, linking the enzyme mechanism directly to the human postprandial result in the same paper.

Sun Y et al. — Nutrients

Across eight observational studies, higher circulating lycopene was associated with lower carotid artery wall thickness, a marker of subclinical atherosclerosis; beta-carotene showed only a marginal association and the link was stronger in men.

Cavero-Redondo I, Saz-Lara A, Saz-Lara AD, Martínez-Cifuentes Ó, Otero-Luis I, González-Collado A, Rey-López JP. — Nutrients

Updated tolerable upper intake levels for preformed vitamin A and beta-carotene.

EFSA Scientific Opinion, 2024 — PMC11154838

This review explains hypercarotenemia -- harmlessly elevated blood carotenoids causing yellow-orange skin with clear whites of the eyes -- distinguishing it from jaundice and framing it as a benign biomarker of carotenoid intake and beta-carotene-conversion genetics.

Wang Z, Xu J, Xu G, Sha Y, Wang K, Chen G. — Cureus

Plasma vitamins A D and K generally not materially changed -- Alpha-tocopherol and beta-carotene commonly decreased

Fardet A et al. — Critical Reviews in Food Science and Nutrition

In a German total diet study measuring retinol across 333 foods, animal livers and liver-based products carried the highest preformed vitamin A levels of any food group after cod liver.

Schendel S; Berg T; Scherfling M; Drosser C; Ptok S; Weissenborn A; Lindtner O; Sarvan I — Food Chemistry: X

Using genetic (Mendelian randomization) methods, this study found no consistent causal link between higher circulating dietary antioxidants, including beta-carotene, and better lung function, even in people exposed to smoke or air pollution.

Saied A, Horsfall LJ. — Canadian respiratory journal

Review proposes that bioactive compounds in sweet potato root, including beta-carotene and resveratrol, may support collagen synthesis and counter age-related wrinkles and loss of skin firmness when used orally or topically.

Bibi A; Maqsood S; Arshad MT; Ikram A; Gnedeka KT — Food science & nutrition

In northern-Chinese mothers, carotenoids transferred into breast milk shifted over lactation -- beta-carotene predominated in colostrum and lutein in mature milk -- and milk levels partly tracked mothers' dietary carotenoid intake.

Tian L, Wang L, Li F, Sun A, Ni M, Sun H, Wang H, Li X, Zhao Y, Zhang L, Li X, Kuchan M, Mao Y, Chen J. — Food & function

Tart cherry's mix of anthocyanins, polyphenols, and beta-carotene appears to reduce oxidative stress and inflammation through epigenetic and metabolic pathway changes, per a review of its bioactive components.

Xu J; Pan Y; Peter RM; Chou PJ; Dave PD; Shanner A; Sarwar MS; Brunetti L; Simon JE; Kong AT — Current pharmacology reports

In adults over 50, higher dietary lutein and zeaxanthin intake was associated with lower odds of vertebral fracture, and beta-carotene with lower fracture odds in women, suggesting carotenoid-rich diets may support bone -- an association, not proof of cause.

Zheng Y, Zhou W, Zhang J, Lan T, Zhang R. — Archives of osteoporosis

A review comparing vitamin bioavailability found animal-sourced foods are the main source of highly bioavailable vitamin B-12 (65%) and retinol (74%), along with notably bioavailable biotin, folate, niacin, and thiamin.

Chungchunlam SMS; Moughan PJ — Critical reviews in food science and nutrition

Lycopene and beta-carotene are vitamin A precursor carotenoids that provide antioxidant defense against cellular peroxides, with research linking their intake to lower cardiovascular disease and cancer risk and improved eye health.

Tufail T; Bader Ul Ain H; Noreen S; Ikram A; Arshad MT; Abdullahi MA — Food science & nutrition

A review of lycopene digestion and metabolism notes it is unclear whether health associations, including with certain cancers and cardiovascular disease, stem from lycopene itself or its breakdown products.

Arballo J; Amengual J; Erdman JW — Antioxidants (Basel, Switzerland)

Micronutrient bioavailability in biofortified crops depends on food matrix, processing, and dietary fat, with conversion efficiency for provitamin A carotenoids and iron and zinc absorption varying by crop type.

Bechoff A; Dhuique-Mayer C — Annals of the New York Academy of Sciences

In laboratory tests, nanoliposome-encapsulated beta-carotene and a carotenoid-rich microalgae extract protected red blood cells from oxidative damage through sustained antioxidant release, with the whole extract outperforming isolated beta-carotene.

García-Morales J, González-Vega RI, Fimbres-Olivarría D, Bernal-Mercado AT, Auobourg-Martínez SP, López-Gastélum KA, Burruel-Ibarra SE, Silvas-García MI, Grijalva-Molina A, Ornelas-Paz JJ, Del-Toro-Sánchez CL. — Molecules (Basel, Switzerland)

This systematic review describes how carotenoids protect aging skin through antioxidant action, support of hydration and elasticity via aquaporin and hyaluronic-acid pathways, and modulation of mitochondrial function, highlighting their potential in preventive dermatology.

Stanescu C, Chiscop I, Mihalache D, Popa F, Tamas C, Stoleriu G. — Nutrients

Pooling randomized trials, this meta-analysis found dietary supplements including carotenoids and collagen peptides associated with small but measurable improvements in skin photoaging markers.

Study authors per publication — Frontiers in Medicine

Most RCTs reported improvement in at least some cognitive domains -- No single pooled effect and brain-activity findings inconsistent

García-Romera MC et al. — Source not captured in pack

This systematic review concludes carotenoids support skin structure and antioxidant defense through several overlapping mechanisms, while cautioning that clinical effect sizes vary by study and carotenoid type.

Study authors per publication — Nutrients

Retinol and vitamin D were not materially affected -- Several carotenoids decreased even after cholesterol standardization

Baumgartner S et al. — European Journal of Nutrition