CLA Supplements & Anemia: What You Need to Know

study PMID: 40120349

Quick Summary: A recent study in mice found that taking CLA supplements led to a type of anemia. This means the mice had fewer red blood cells, and their bodies weren't working as well to make new ones.

What The Research Found

This study looked at the effects of CLA (conjugated linoleic acid) supplements on mice. The researchers found that mice taking CLA developed anemia, a condition where you don't have enough healthy red blood cells. Here's what they saw:

Fewer Red Blood Cells: Mice taking CLA had significantly fewer red blood cells.

Larger Red Blood Cells: The red blood cells that were present were larger than normal.

Increased Breakdown of Red Blood Cells: The mice showed signs of their bodies destroying red blood cells faster than usual.

Lower Vitamin Levels: The mice had lower levels of important vitamins like B12 and folate.

Study Details

Who was studied: Male Kunming White mice.

How long: The study lasted for about 3 months (86 days).

What they took: Mice were given a diet supplemented with CLA. A control group received a similar diet without CLA.

What This Means For You

This study was done on mice, so we can't say for sure if the same thing would happen to humans. However, it raises some important questions about CLA supplements:

Anemia Risk: If you take CLA supplements, it might be a good idea to talk to your doctor about getting your blood checked, especially if you feel tired or weak.

Nutrient Absorption: The study suggests that CLA might affect how your body absorbs important nutrients like B12 and folate.

More Research Needed: Scientists need to do more research to see if CLA supplements have similar effects on humans and to determine safe dosages.

Study Limitations

It's important to remember that this study has some limitations:

Animal Study: The study was done on mice, not humans. Results in mice don't always translate to humans.

Dosage Unknown: The exact amount of CLA the mice received wasn't specified, making it hard to compare to human supplement doses.

Short Duration: The study only lasted 3 months, so we don't know the long-term effects.

Key Findings

This 2025 study found that dietary CLA supplementation in male Kunming White mice induced anemia with combined megaloblastic and hemolytic features. Key outcomes included:
- 48.96% lower RBC count (p < 0.01) and 46.49% reduced hematocrit (p < 0.01) in CLA-fed mice.
- Increased mean corpuscular volume (MCV) by 7.82% (p < 0.01), indicating larger red blood cells.
- 41.77-fold higher monocyte proportion (MONO %, p < 0.001) and reticulocyte counts exceeding twice those of controls (p < 0.01), suggesting accelerated RBC turnover.
- Decreased plasma vitamin B12 (24.72%) and folate (23.15%) levels (p < 0.05 and p < 0.01, respectively), alongside elevated direct bilirubin (p < 0.05), pointing to nutritional deficiencies and hemolysis.
- Enhanced phagocytic activity of liver Kupffer cells observed via electron microscopy.
No differences were noted in RBC osmotic fragility, plasma iron, or renal EPO mRNA expression.

Study Design

Type: Controlled animal study (mice).
Participants: Male Kunming White mice (sample size unspecified).
Groups: CLA-supplemented diet vs. linoleic acid (LA)-supplemented control diet.
Duration: 86 days.
Methods: Periodic erythrocyte counts, CBC analysis, BCB-stained reticulocyte assessments, plasma biomarker measurements, and electron microscopy of liver tissue.

Dosage & Administration

CLA administration: Dietary supplementation (specific dose unspecified).
Control: Linoleic acid (LA)-supplemented diet.
Duration: Continuous supplementation for 86 days.

Results & Efficacy

RBC reduction: CLA group showed significant decreases at day 47 (p < 0.05), day 61 (p < 0.01), and day 86 (p < 0.001).
Hematocrit (HCT): 46.49% lower in CLA group (p < 0.01).
MCV: 7.82% higher in CLA group (p < 0.01).
Reticulocytes: >2x higher in CLA group (p < 0.01).
Monocyte proportion: 41.77-fold increase (p < 0.001).
Nutritional deficiencies: Vitamin B12 (-24.72%, p < 0.05) and folate (-23.15%, p < 0.01) reduced.
Hemolysis marker: Direct bilirubin increased significantly (p < 0.05).

Limitations

Unspecified sample size: Limits reproducibility and statistical power assessment.
Animal model: Findings may not generalize to humans.
No dose-response data: CLA dosage details were omitted, hindering comparison with human-relevant doses.
Short-term duration: 86 days may not capture long-term effects or recovery potential.
Mechanistic gaps: No exploration of CLA’s direct molecular impact on nutrient absorption or immune activation.

Clinical Relevance

This study raises concerns about CLA supplementation potentially causing anemia in mice through nutritional deficiencies (B12/folate) and immune-mediated RBC destruction. While human extrapolation is premature, supplement users should consider:
- Monitoring B12/folate levels during prolonged CLA use.
- Investigating unexplained elevated reticulocytes or bilirubin as possible hemolysis indicators.
- Caution in populations at risk for anemia or nutrient deficiencies.
Further research is needed to determine if these effects occur in humans and to establish safe dosing thresholds.

Source (PubMed, 2025)