Nutritional Factor F: Applications, Origins, and Potential Hazards
Alpha-linolenic acid (ALA) and linoleic acid (LA), colloquially known as "vitamin F," are essential omega fatty acids that the body cannot synthesize and must obtain from the diet.
Recommended dietary sources of ALA include plant foods such as flaxseeds, walnuts, chia seeds, and other seeds and nuts. LA, on the other hand, is primarily found in various plant seed oils—for example, safflower, sunflower, corn, and soybean oils. ALA is an omega-3 fatty acid, whereas LA is an omega-6 fatty acid.
The potential health benefits of ALA include acting as a precursor to longer-chain omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which have well-documented cardio-protective effects such as lowering LDL cholesterol, reducing triglycerides, and decreasing inflammation. ALA itself contributes to reducing systemic inflammation and supports heart health, though the body converts only a small fraction of ALA into EPA and DHA. EPA and DHA support brain and retinal development and may benefit mood disorders and cognitive functions.
Linoleic acid (LA) serves as a precursor for other biologically important omega-6 fatty acids, including gamma-linolenic acid (GLA), which has anti-inflammatory, immune-modulating, and cardiovascular protective effects.
People who eat a vegan diet may need higher ALA amounts to avoid deficiency and may need to decrease LA to achieve a good ratio of omega-6 to omega-3. This is because a diet favoring omega-6 is pro-inflammatory and contributes to atherosclerosis, obesity, and diabetes.
In some cases, individuals may experience symptoms of deficiency, but these are not routinely tested. Signs of deficiency may not always be apparent. However, the Linus Pauling Institute identifies a dry, scaly rash, decreased growth in children and infants, increased susceptibility to infection, poor wound healing, and cognitive impairment as clinical signs of essential fatty acid deficiency.
Topical application of olive oil or sunflower seed oil may reduce symptoms of scaliness. Regular inclusion of ALA and LA sources supports overall health, particularly cardiovascular and inflammatory status, while also ensuring essential fatty acid needs are met.
It's important to note that there are no dietary reference intakes (DRIs) for ALA or LA in the United States, and experts set an adequate intake (AI) based on the highest median intake among adults.
In summary, a balanced diet that includes a variety of plant-based sources of ALA and LA can contribute significantly to maintaining overall health and well-being.
- The health-and-wellness benefits of consuming ALA from foods like flaxseeds and walnuts extend to supports for heart health and systemic inflammation reduction.
- Linoleic acid, primarily found in plant seed oils such as safflower and sunflower, acts as a precursor to gamma-linolenic acid, a fatty acid with anti-inflammatory, immune-modulating, and cardiovascular protective effects.
- A healthy diet rich in ALA from sources like chia seeds and nuts, and LA from oil sources like soybean and sunflower, contributes to essential fatty acid needs essential for overall health, including maintaining a proper balance of omega-6 to omega-3 ratios.
- While there are no official dietary reference intakes (DRIs) for ALA or LA in the United States, regular inclusion of these omega fatty acids in one's diet can support fitness-and-exercise performance, a healthy-diets lifestyle, and skin-care.
- A deficiency in essential fatty acids, caused by an imbalance in omega-6 to omega-3 intake or insufficient consumption, may lead to clinical signs such as a dry, scaly rash, poor wound healing, cognitive impairment, or increased susceptibility to infection, as identified by the Linus Pauling Institute.
