Insights on the Keto Diet and Multiple Sclerosis
A ketogenic diet—characterized by low carbohydrates and high fats—rich in long-chain, saturated fatty acids like those found in butter and fatty red meat, hasn’t managed to reduce optic nerve damage in a mouse model of multiple sclerosis (MS), according to new research.
Interestingly, offering this diet to mice prior to the onset of disease seemed to slightly worsen certain visual issues. It’s been commonly suggested that ketogenic diets might help with inflammation in MS patients, but these findings indicate that the type of fat consumed could be crucial in evaluating these diets as a treatment option.
As the researchers noted, “We present new data that the use of [the ketogenic diet] in the treatment of MS should take the composition of the [the ketogenic diet] into consideration.” This perspective appeared in their study titled “A high-saturated, long-chain fatty acid ketogenic diet negatively impacts visual and motor-sensory function in a pre-clinical model of multiple sclerosis,” published in Frontiers in Immunology.
MS is linked to immune-related damage in the brain and spinal cord, which leads to various neurological symptoms. One early indicator of MS can be optic neuritis, which is inflammation of the optic nerve, and this can result in various vision problems like blurred vision and challenges with color perception or depth.
The ketogenic diet originated for managing seizure disorders but may also have anti-inflammatory benefits. This diet compels the body to utilize fat rather than sugar for energy.
Some research has indicated that a keto diet might alleviate fatigue, enhance exercise capacity, boost cognition, and improve hand dexterity in those with MS. Nonetheless, results from mouse studies have been mixed. The researchers pointed out that differing results could arise from the use of medium-chain vs. long-chain fatty acids in various studies.
They emphasized the need for additional analysis of the keto diets used in MS research and how the length and saturation of fatty acids might affect the outcomes.
Examination of Keto Diet Impact on MS Mouse Model
Researchers from the University of Iowa looked into how a keto diet composed of long-chain, saturated fatty acids affected optic neuritis in mice with experimental autoimmune encephalomyelitis (EAE), a condition commonly used to simulate MS.
Long-chain, saturated fatty acids are typically found in red meats, dairy products, as well as coconut and palm oils.
The mice were placed on either a keto or standard diet, administered before disease onset, during induction, or at symptom manifestation. The researchers evaluated disease severity along with optic neuritis by measuring visual acuity and electrical activity in the optic nerve, along with imaging and tissue analysis.
Mice that started the keto diet before EAE induction exhibited considerably worsened disease severity compared to those on a standard diet. However, no significant differences appeared when the diet was begun at the time of disease induction or when symptoms emerged.
Visual acuity also declined more severely in the mice that were pretreated with the keto diet. Conversely, when the diet was introduced later, the outcomes did not differ significantly.
As the researchers suggested, “We propose that pretreatment with a long-chain, saturated [ketogenic diet] … leads to an initial priming of the immune system that results in a more robust immune response and inflammatory cascade when disease induction occurs.”
That said, some aspects of optic nerve health didn’t show changes based on diet. Imaging of the retina indicated similar thinning of nerve layers across all EAE groups, regardless of diet. Additionally, the strength and speed of visual signals in EAE mice were impaired compared to healthy ones, but these impairments were consistent across diet groups. Tissue analyses yielded similar levels of optic nerve damage in EAE mice across all the diet variations.
Ultimately, the researchers concluded, “Our results demonstrate that irrespective of the timing of its implementation, a long-chain, saturated fatty acid [ketogenic diet] does not significantly improve visual outcomes in EAE mice.” They stressed the importance of not just considering the quantity of specific macronutrients but also the composition of fats when looking at ketogenic diets in the context of managing MS.
