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Head-to-head evidence comparison — which supplement is right for you?
Calcium wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Likely helps
18 of 20 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
5 of 5 studies with measurable effects showed benefit.
Top outcomes
1000–1200mg daily (split doses)
Split doses with meals, 500mg with breakfast, 500mg with dinner
Calcium Citrate
5-6g daily
With meals, Can be added to drinks or food
PHGG powder (Sunfiber is common brand)
PHGG may modestly improve calcium absorption through colonic fermentation pathways, similar to but less potent than inulin. The fiber also may reduce calcium-induced constipation (a common side effect of calcium carbonate) by improving bowel motility.
PHGG (5 g/day) can be combined with calcium supplementation to improve GI tolerance and potentially enhance colonic calcium absorption. Particularly useful for elderly individuals prone to calcium-induced constipation.
6-24 months
12-36 months
Throughout pregnancy
Within days of starting
1-2 weeks
2-4 weeks
2-4 weeks
Effects of combined calcium and vitamin D supplementation on osteoporosis in postmenopausal women: a systematic review and meta-analysis of randomized controlled trials.
Food & Function (2020) · Meta analysis · n=12000
Combined calcium and vitamin D significantly improved lumbar spine BMD in postmenopausal women
Association Between Calcium or Vitamin D Supplementation and Fracture Incidence in Community-Dwelling Older Adults: A Systematic Review and Meta-analysis.
JAMA (2017) · Meta analysis · n=51145
33 trials involving 51,145 participants were analyzed
Vitamin D and Calcium for the Prevention of Fracture: A Systematic Review and Meta-analysis.
JAMA Network Open (2019) · Meta analysis · n=51419
Meta-analysis of 11 randomized clinical trials with 51,419 participants
Effectiveness of Partially Hydrolyzed Guar Gum on Cognitive Function and Sleep Efficiency in Healthy Elderly Subjects in a Randomized, Double-Blind, Placebo-Controlled, and Parallel-Group Study
Nutrients (2024) · Rct
The visual memory scores in cognitive function tests and sleepiness on rising scores related to sleep quality were significantly improved in the PHGG group compared to the placebo group.
Continuous partially hydrolyzed guar gum intake reduces cold-like symptoms: a randomized, placebo-controlled, double-blinded trial in healthy adults
European review for medical and pharmacological sciences (2022) · Rct · n=96
PHGG intake may affect immune function and suppress cold-like symptoms through the production of SCFAs in healthy adults.
Prebiotic Effects of Partially Hydrolyzed Guar Gum on the Composition and Function of the Human Microbiota-Results from the PAGODA Trial
Nutrients (2020) · Rct · n=20
To gain functional insight, we further studied stool metabolites using nuclear magnetic resonance (NMR) spectroscopy. (3) Results: In healthy subjects, PHGG had significant effects on stool frequency and consistency.
Based on meta-analysis of 59 RCTs showing 0.6-1.8% BMD increases. Requires vitamin D co-supplementation for optimal effect. Effectiveness plateaus beyond 1200mg daily.
Based on multiple RCTs showing symptom improvement in IBS patients. Studies show benefits in both constipation-predominant and diarrhea-predominant IBS. Effect diminished at follow-up in some studies.
AI-estimated from published studies. Interpret as directional guidance.
Calcium has a higher evidence score (8/10 vs 6/10) and wins in 2 of 3 categories.
For improve digestion, PHGG has a higher relevance score (87 vs 30).
Calcium and PHGG may work well together: PHGG may modestly improve calcium absorption through colonic fermentation pathways, similar to but less potent than inulin. The fiber also may reduce calcium-induced constipation (a common side effect of calcium carbonate) by improving bowel motility. PHGG (5 g/day) can be combined with calcium supplementation to improve GI tolerance and potentially enhance colonic calcium absorption. Particularly useful for elderly individuals prone to calcium-induced constipation.