Table 1.

Studies involving creatine supplementation in vegetarians.

Study	Participants	Design	Results
Solis et al. [33]	8 male, 6 female vegetarians (4 vegan, 9 lacto–ovo, 1 ovo); duration vegetarian ~10 y 11 male, 6 female omnivoresMean age ~30 y Approximately equal number in each group classified as having low, moderate, and high levels of physical activity	Non-randomized cross-over study Participants were given placebo for 7 d, then 0.3 g Cr/kg/d for 7 d	Gastrocnemius PCr increased by 25% after Cr supplementation in vegetarians with no increase in omnivores. Gastrocnemius PCr was about 5% lower before Cr supplementation in vegetarians but 17% higher after Cr supplementation versus omnivores. Brain PCr: no change in either group with Cr supplementation.
Blancquaert et al. [34]	40 female omnivores Mean age ~26 y	RCT n = 10 controls n = 15 given a lacto–ovo vegetarian diet for 6 months + 1 g Cr/d n = 15 given lacto–ovo vegetarian diet for 6 months + placebo	After 3 months: Vastus lateralis TCr decreased 15% with vegetarian + placebo; increased 9.7% with vegetarian + Cr; increased 6.8% with control. After 6 months: Plasma Cr decreased 46% with vegetarian + placebo; increased 195% with vegetarian + Cr; no change with control. Performance on an incremental cycling test to exhaustion: no change. over the 6 months
Shomrat et al. [35]	7 male vegetarians 17 male omnivores Active, but not highly trained Mean age ~28 y	Non-randomized prospective 9 omnivores and the 7 vegetarians received 3 × 7 g Cr/d for 6 d 8 omnivores received placebo	Performance on 3 × 20 s modified Wingate maximal cycling tests with 4 min recovery between bouts: Mean power output increased 5% in vegetarians and omnivores supplemented with Cr, but not with placebo. Peak power output increased 5% only in omnivores on Cr.
MacCormick et al. [36]	6 female vegetarians 6 female omnivores Mean age ~22 y Physically active, but not athletes	Prospective Participants were given 0.3 g Cr/kg LTM/d for 5 d	Vegetarians increased Cr in erythrocytes (140%) and plasma (258%); omnivores increased Cr in erythrocytes (53%) and plasma (116%). At 5 d, vegetarians had 89% higher plasma Cr compared to omnivores.
Watt et al. [37]	7 male vegetarians (4 vegans, 3 lacto–ovo vegetarians), at least 6 months duration vegetarian; mean age 23 y 7 male omnivores, mean age 28 y	Randomized cross-over study 0.4 g Cr/kg/d or placebo for 5 d 5-week washout	Vastus lateralis TCr increased 76% in vegetarians with Cr supplementation versus 35% in omnivores. Vastus lateralis PCr increased by ~31% in both groups with Cr supplementation. Vastus lateralis TCr was lower in vegetarians at baseline, but 12% higher than omnivores after 5 d Cr supplementation. Vastus lateralis Cr transporter mRNA increased 1 d into Cr supplementation in both groups, then returned to baseline levels at 5 d. 2 × 30 s Wingate maximal cycling test with 4 min recovery between bouts: Cr supplementation increased mean power output for both groups on the 2nd bout.
Lukaszuk et al. [17,43]	26 male omnivores Mean age 23.5 y Physically active, but not strength trained	RCT n = 14 controls n = 12 given lacto–ovo vegetarian diet for 26 dOn day 22: Participants were randomized to receive 0.3 g Cr/kg or placebo	After 21 d, participants who were given the lacto–ovo diet decreased vastus lateralis TCr (9.5%), PCr (8.7%), Cr (11%), and plasma Cr (9.1%). From day 22 to 27, TCr increased in the vegetarian Cr-supplemented group (20%) and the omnivorous Cr-supplemented group (10%) compared to the vegetarian placebo group (−2%) and the omnivorous placebo group (0%). Plasma Cr increased across Cr supplementation groups (13.3%) compared to placebo groups (0.5%).
Burke et al. [18,44]	8 male, 10 female vegetarians (3 vegans, 15 lacto–ovo vegetarians; vegetarian duration at least 3 y) 12 male, 12 female omnivores All participants were recreational athletes (walking, jogging, swimming, cycling) with 1–5 y resistance training experience Mean age ~33 y	RCT n = 5 male, 5 female vegetarians and 7 male, 5 female omnivores given 0.25 g Cr/kg LTM/d for 7 d, 0.0625 Cr/kg LTM/d for 49 d n = 3 male, 5 female vegetarians and 5 males, 7 female omnivores given placebo for 56 d All participants engaged in a high-volume resistance training program (training all major muscle groups) for 56 d	Vegetarians on Cr had greater increase in vastus lateralis PCr (+66%) than omnivores on Cr (+19%), vegetarians on placebo (−18%), and omnivores on placebo (+6%). Vegetarians on Cr had greater increase in vastus lateralis TCr (+30%) than omnivores on Cr (+8%), vegetarians on placebo (−4%), and omnivores on placebo (+4%). Vegetarians on Cr increased lean tissue mass 2.4 kg, which was greater than omnivores on Cr (1.9 kg) and other groups (1 kg). Vegetarians on Cr had greater increase in total work during 50 isokinetic knee extensions/flexions (30%) than omnivores on Cr (9%), vegetarians on placebo (8%), and omnivores on placebo (4%). Both creatine groups increased bench press strength, type II vastus lateralis fiber area, and muscle insulin-like growth factor-1 more than placebo groups.
Benton et al. [45]	70 female vegetarians 51 female omnivores Mean age ~20.3 y	RCT Participants given either 20 g Cr/d or placebo for 5 d	Memory was enhanced in vegetarians on Cr, but not omnivores.
Rae et al. [46]	45 vegetarians (12 males, 33 females; 18 vegans for median duration 4.6 y; 27 lacto–ovo vegetarians for median duration 14.3 y) Mean age ~26 y	Randomized cross-over study 6 weeks with 5 g Cr/d or placebo 6-week washout	Working memory and intelligence were increased during creatine compared to placebo supplementation.

Abbreviations: Cr = creatine; LTM = lean tissue mass; PCr = phosphocreatine; RCT = randomized controlled trial; TCr = total creatine.