HoldsUp

FoundMyFitness · 2020-05-13 · Rhonda Patrick (host)

Vitamin C: Oral vs. Intravenous, Immune Effects, Cancer, Exercise Adaptation & More

75 claims checked against research: 4 contradicted 4 overstated 7 needing context 50 supported 10 unverified

4

Contradicted by research

0:12:46Rhonda Patrick (host)contradictedhigh

A blood concentration of approximately 50 micromoles per liter of vitamin C is necessary to prevent the oxidation of LDL cholesterol.

"The idea behind the different RDAs is that research shows that consuming these amounts will maintain the optimal blood concentration of approximately 50 micromoles per liter of blood, a concentration necessary to prevent oxidation of LDL cholesterol." (said at 0:12:46)

The statement misrepresents how the Dietary Reference Intakes and Recommended Dietary Allowance (RDA) for vitamin C were established. The RDA (currently 90 mg/day for men and 75 mg/day for women) is based on pharmacokinetics, near-saturation of neutrophil and leukocyte intracellular stores, urinary excretion thresholds, and steady-state plasma concentrations (~50–60 µmol/L to provide antioxidant protection while preventing deficiency). It is not defined as a requirement 'necessary to prevent oxidation of LDL cholesterol.' Furthermore, controlled pharmacokinetic depletion-repletion trials in humans have demonstrated that varying vitamin C doses and reaching normal plasma saturation do not significantly alter endogenous markers of lipid peroxidation (such as F2-isoprostanes) in healthy volunteers, and preventing LDL oxidation is not the biological benchmark or rationale upon which the RDA was derived.

1:07:06Rhonda Patrick (host)contradictedvery low

An in vitro study found that incubating virus-infected cells for 4 days with 150 micrograms per milliliter of vitamin C reduced reverse transcriptase activity by 99% and p24 antigen levels by 13%.

"One in vitro study showed that in virus-infected cells that were incubated for four days with 150 micrograms per milliliter of vitamin C, decreased parameters of virus production, such as reverse transcriptase activity by 99% and p24 antigen levels by 13% compared to untreated cells." (said at 1:07:06)

A 1990 in vitro study investigated the effect of ascorbate (vitamin C) on HIV-1 replication in chronically infected T-lymphocytic cell lines. The study found that ascorbate reduced extracellular reverse transcriptase activity by greater than 99% and reduced p24 antigen levels by 90% in the culture supernatant, not by 13% as stated. Because the speaker misquotes the reported reduction in p24 antigen (90% reduction vs. 13%), the claim as stated is contradicted by the published record. Furthermore, these findings represent in vitro cell-culture data and do not demonstrate clinical efficacy in humans.

1:10:00Rhonda Patrick (host)contradictedmoderate

Case reports indicate that intravenous vitamin C administered at doses between 1 and 10 grams can reduce hemolysis in G6PD-deficient patients.

"Other case reports have indicated that when given at a dose between 1 to 10 grams, intravenous vitamin C can reduce hemolysis." (said at 1:10:00)

Intravenous vitamin C does not reduce hemolysis in glucose-6-phosphate dehydrogenase (G6PD) deficiency; rather, it is well documented as a trigger that induces acute hemolytic anemia in G6PD-deficient individuals. A literature review of published case reports of vitamin C-induced hemolysis found that 71.4% of patients had G6PD deficiency, with causative doses ranging from 1 to 200 g/day across oral and intravenous routes. While moderate doses of intravenous ascorbic acid (e.g., 1 to 10 g) have occasionally been reported as an alternative reducing agent to treat methemoglobinemia when methylene blue is contraindicated, high-dose or intravenous vitamin C remains contraindicated in G6PD deficiency due to the significant risk of precipitating or worsening hemolysis.

1:11:10Rhonda Patrick (host)contradictedmoderate

Two large prospective cohort studies found an association between high vitamin C intake and increased relative risk of kidney stones in multivariate analysis, but found no statistically significant association on univariate analysis.

"Two large prospective cohort studies involving tens of thousands of people found that high vitamin C intake increases the relative risk of kidney stones, but the findings are slightly misleading because they didn't report the actual incidence rate of kidney stones. The higher risk was only found after statistical manipulation of the data, and the patients with higher vitamin C intake actually did not have more kidney stones. I'm going to go on a little statistical tangent, because I find it very misleading that two studies found no association between vitamin C intake and kidney stone risk doing a univariate analysis, but then went on to do a multivariate analysis." (said at 1:11:10)

Published prospective cohort studies tracking tens of thousands of participants do not show that an association between vitamin C and kidney stones was artificially generated solely by multivariate adjustment while showing no effect in unadjusted or age-adjusted analyses. In the Health Professionals Follow-up Study (HPFS) and Nurses' Health Study cohorts, total and supplemental vitamin C intake was prospectively associated with a significantly higher risk of incident kidney stones among men (multivariable HR 1.43, 95% CI 1.15–1.79 for ≥1,000 mg/day in Ferraro et al. 2016; RR 1.41, 95% CI 1.11–1.80 in Taylor et al. 2004). In earlier 6-year follow-up of HPFS men (Curhan et al. 1996), high vitamin C intake showed no significant association in age-adjusted analysis (RR 0.78, 95% CI 0.54–1.11) and this did not change significantly after multivariate adjustment.

Unverified means no publication matching the claim was located; it does not prove the claim false. Spotted an error? See the corrections policy - disputes from the people quoted are prioritized.