Who Should Avoid Taking CLA Supplements?
While some market conjugated linoleic acid (CLA) as a weight loss aid, research consistently shows modest and often unreliable results, especially compared to the well-documented side effects and risks. For several groups, the potential for harm far outweighs any perceived benefit, making CLA supplements a poor choice.
Individuals with Diabetes or Metabolic Syndrome
One of the most significant contraindications for CLA is having diabetes or metabolic syndrome. Several studies have raised concerns that CLA can worsen insulin resistance, the body's decreased ability to respond to insulin, leading to higher blood sugar levels. In those with metabolic syndrome—a cluster of conditions including high blood pressure, high blood sugar, and excess body fat around the waist—CLA supplementation might increase the risk of developing full-blown diabetes. For anyone managing their blood sugar, this effect can be particularly dangerous and destabilizing.
People with Liver Conditions
High doses of supplemental CLA, which are different from the small amounts found naturally in foods, have been shown to cause liver fat accumulation in some individuals and animal studies. This condition, known as liver steatosis or fatty liver, can potentially lead to more serious liver complications over time. People with pre-existing liver disease should therefore steer clear of CLA supplements to avoid exacerbating their condition.
Pregnant and Breastfeeding Women
There is insufficient reliable information to confirm the safety of CLA supplements during pregnancy and breastfeeding. Given the lack of robust safety data, healthcare professionals advise erring on the side of caution. While natural CLA from foods like beef and dairy is likely safe, the high, concentrated doses found in supplements are best avoided during these sensitive periods.
Children and Adolescents
The long-term safety of CLA supplements for children has not been adequately studied. Because a child's metabolism and developing body can react differently to supplements, experts recommend against giving CLA to minors. Their bodies are best served by naturally occurring fats found in a balanced, healthy diet.
Patients with Bleeding Disorders or Prior to Surgery
CLA supplements may slow blood clotting. For individuals with a bleeding disorder or anyone scheduled for surgery, this effect could increase the risk of excessive bleeding or bruising. The recommendation is to stop taking CLA supplements at least two weeks before any planned surgical procedure to mitigate this risk.
Who Should Exercise Extreme Caution?
Beyond the groups who should avoid CLA entirely, others need to be extremely cautious and discuss use with a healthcare provider.
- Individuals on Medication: CLA can interact with various medications. For example, it can lower blood pressure, potentially causing it to drop too low when combined with antihypertensive drugs. It can also interfere with blood-thinning medications like aspirin and warfarin. Those taking insulin or other diabetes medications may require dose adjustments due to CLA's effect on insulin resistance.
- Those with High Cholesterol: While some studies show mixed effects on cholesterol, some research indicates that supplemental CLA can lower 'good' HDL cholesterol. Anyone with a history of heart disease or cholesterol issues should be monitored closely.
Comparison of CLA from Supplements vs. Food
The source of CLA is a critical factor influencing its effects and safety. This table highlights the key differences.
| Feature | Supplemental CLA | Naturally Occurring CLA (Food) |
|---|---|---|
| Source | Chemically altered from vegetable oils (e.g., safflower oil) | Found naturally in meat and dairy from ruminant animals |
| Dose | High, concentrated doses typically 3-6 grams per day | Low, typically around 150-212 mg per day in the US diet |
| Isomers | Different, often specific isomers with varying effects | Diverse, balanced mix of isomers |
| Health Impact | Associated with risks like insulin resistance, liver fat, and reduced HDL | Correlated with overall better metabolic health in long-term observational studies |
Mild to Moderate Side Effects
Even for those not in a high-risk group, CLA supplements can cause common, less severe side effects. The most frequently reported issues include digestive problems such as upset stomach, nausea, diarrhea, and indigestion. Some users also experience fatigue and headaches. Taking CLA with food can sometimes help mitigate these gastrointestinal effects.
Conclusion
For individuals with pre-existing health conditions like diabetes, metabolic syndrome, or liver problems, as well as pregnant and breastfeeding women and children, the potential risks of CLA supplements outweigh the unproven benefits. Furthermore, those on certain medications or with high cholesterol should use extreme caution and consult a healthcare provider before starting CLA. It is vital to recognize the distinction between the high doses and different isomers found in supplements and the small amounts of natural CLA consumed through a healthy diet. Always prioritize consultation with a medical professional to ensure any supplement is safe and appropriate for your individual health needs.
Potential Side Effects List
- Gastrointestinal upset (nausea, diarrhea, stomach pain)
- Increased insulin resistance
- Fat accumulation in the liver
- Lower levels of 'good' HDL cholesterol
- Potential for increased inflammation markers
- Increased risk of bleeding in those with clotting disorders or pre-surgery
- Interactions with blood pressure, diabetes, and blood-thinning medications
