The Sciatic Nerve

The sciatic nerve is the largest nerve in the body and is formed by five nerve roots that converge and exit the lower spine. It runs through the buttocks on either side and down the thighs to the heels and soles of the feet. The sciatic nerve connects the spinal cord to the muscles of the thigh, leg, and foot. Any type of pain and/or neurological symptoms that originate from the sciatic nerve are known as sciatica. The symptoms can be felt along the nerve’s path. This could be the:

• Low back
• Buttocks
• Thighs
• Calves
• Feet
• Or it could be a combination of all the areas

 

Neurological Symptoms

When the nerve is compressed, neurological symptoms can accompany the pain. These include:

Thigh muscle weakness

If the thigh muscles are affected, weakness can be felt when bending or flexing the knee.

Leg and foot muscle weakness

Weakness can be felt while attempting to bend the knee or point the foot/toes upward/downward. This can lead to foot drop, making it difficult to lift the front of the foot while walking. Difficulty can also present when getting up from a sitting position or walking on the tiptoes.

Numbness

Loss of sensation can occur when nerve impulses cannot pass all the way through. Common areas affected by numbness are the:

• Side of the calf
• Side of the heel
• Bottom of the foot
• Top of the foot

Paresthesia

This is an abnormal sensation felt on the skin. It is brought on by improper nerve transmission. This sensation can include:

• Tingling
• Tightness
• Pins-and-needles
• Crawling feeling along the back of the thigh and/or leg

The Sciatic Nerve Gets Affected

The sciatic nerve can become:

• Irritated
• Compressed
• Inflamed
• This lumbar/low back radiculopathy means that the pain originates in and around the lumbar and/or sacral/sacrum nerve roots.

Compression

Physical forces could affect the nerve following common conditions:

Disc Herniation

A disc in the lower back can bulge or herniate. This causes irritation that can lead to nerve root compression.

Stenosis

Stenosis means the opening where the sciatic nerve exits the buttocks begins to narrow. This creates a clog with the other nerve roots, compressing or irritating the sciatic nerve. Degenerative changes in the spine, like the thickening of the facet joint capsules and/or ligaments, can also compress the sciatic nerve.

Instability

Instability of a vertebral segment occurs when one vertebra slips over the one below it, a condition known as spondylolisthesis. There are also vertebral defects like spondylolysis, which is a complete dislocation of one or more vertebrae. This can directly compress the sciatic nerve roots.

Inflammatory Response

The body’s own chemicals can irritate the nerve, causing inflammation. These chemical irritants include:

• Hyaluronic acid
• Fibronectin protein fragments leak out of degenerated or herniated discs onto and around the sciatic nerve roots.
• There are times when degenerated discs can cause nerve tissues to grow into a disc. The tissue penetrates the outer and inner layers of the disc, causing inflammation and pain.
• Some studies have shown that an immune response can contribute to sciatic pain when there is exposure to disc material from herniated disc (s).

Glycosphingolipids, which are fats, and neurofilaments, which are protein polymers. They are secreted by the immune system and have been found to have high levels in individuals with sciatica. It is believed they are released in reaction to the nerve roots and exposed disc material. This can lead to inflammation of the sciatic nerve.

Body Composition

An individual’s physical characteristics can also affect the sciatic nerve. Research has shown an increased risk of sciatica in:

• Individuals with added weight
• Obese individuals
• Older individuals
• Tall individuals

Work Injuries

Individuals with certain jobs can have an increased risk of developing sciatica. Examples include:

• Semi-Truck operators
• Machine operators
• Construction workers
• Hairstylists
• Office workers
• Athletes who lift weights

This comes from:

• Sitting for long amounts of time
• Poor posture
• Constant bending forward or sideways
• Regularly lifting the arms above shoulder level
• All are risk factors.

Vitamin B12 deficiency

Adequate levels of vitamin B12 are important for nerve health. Vitamin B12 supports the myelin sheath that covers and protects the nerves. It is important for nerve function and impulse transmission. Sciatica can result from vitamin B12 deficiency. However, this is more common in individuals 60+.

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Body Analysis

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Alleviating Nerve Pain Through Clinical Nutrition

Clinical nutrition is a powerful tool for alleviating sciatica. Many individuals can relieve their pain through diet adjustments. Here are a few diet tips to alleviate sciatic nerve pain through clinical nutrition:

• Sometimes, sciatica can be triggered by constipation from an unhealthy diet
• Incorporate fiber-rich foods
• Fruits and vegetables will prevent constipation
• Oily fish like salmon and halibut are rich in omega-3 fatty acids
• Fresh pineapples and berries are anti-inflammatories that support healing and boost the immune system
• 2-3 cups of green tea
• Add turmeric, ginger, and garlic to meals
• B-Vitamins are important to take in when going through sciatica and are found in green peas, spinach, navy beans, nuts, and bananas
• Foods that are rich in A-Vitamins, like dairy products, dark leafy vegetables, orange-colored fruits, eggs, and oily fish
• Foods rich in C-Vitamins, like citrus and tomatoes
• K-Vitamins like  broccoli and spinach
• Drink plenty of water, between 6 and 8 glasses a day

Foods to Avoid

• Nutritionists recommend cutting out meat products except for oily fish for the first two weeks.
• Foods that contain sunflower oil, corn oil, sesame oil, margarine, and partially hydrogenated oil.
• Stressor foods like caffeine, processed food, soda, refined sugars, and chocolate.
• Alcohol

References

Giuffre BA, Jeanmonod R. Anatomy, Sciatic Nerve. [Updated 2018 Dec 16]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482431/.

Heuch I, Heuch I, Hagen K, Zwart JA. Association between body height and chronic low back pain: a follow-up in the Nord-Tr¸ndelag Health Study [published correction appears in BMJ Open. 2015;5(10):e006983]. BMJ Open. 2015;5(6):e006983. Published 2015 Jun 15. doi:10.1136/bmjopen-2014-006983.

Kumar, M. Epidemiology, pathophysiology and symptomatic treatment of sciatica: A review. nt. J. Pharm. Bio. Arch. 2011, 2.

Quero L, Klawitter M, Schmaus A, et al. Hyaluronic acid fragments enhance the inflammatory and catabolic response in human intervertebral disc cells through modulation of toll-like receptor 2 signaling pathways. Arthritis Res Ther. 2013;15(4): R94. Published 2013 Aug 22. doi:10.1186/ar4274.

Shiri R, Lallukka T, Karppinen J, Viikari-Juntura E. Obesity as a Risk Factor for Sciatica: A Meta-Analysis. American Journal of Epidemiology. 2014;179(8):929-937. doi:10.1093/aje/kwu007.