Sprains

Sprains: A Nutrition and Natural-Health Reference

Definition and Overview

A sprain is a soft tissue injury of the ligaments within a joint, often caused by a sudden movement abruptly forcing the joint to exceed its functional range of motion. More precisely, a sprain is an injury to the band of collagen tissue — a ligament — which connects two or more bones to a joint, whose primary function is to provide passive stabilisation of a joint and to play an important role in proprioceptive function.

Ligaments are tough, fibrous bands of connective tissue in the body that connect bones to other bones and help hold important body structures in place, including joints and some organs. Ligaments are tough, inelastic fibers made of collagen that connect two or more bones to form a joint and are important for stability.

A sprain is usually caused by the joint being forced suddenly outside its usual range of movement, stretching the inelastic fibers through too great a range. When a joint is sprained, its torn or stretched ligaments can lose part or all of their ability to reinforce the joint and to keep it moving normally.

Classification and Clinical Presentation

Sprains are classified into three grades according to severity:

• Grade I — mild injury involving microscopic tears and some tenderness.
• Grade II — moderate injury with partial ligament rupture, notable swelling, and tenderness.
• Grade III — serious injury with a complete tear of the ligament.

A sprain is the stretching or tearing of ligaments that attach one bone to another; symptoms include tenderness at the site, swelling, ecchymosis, and pain with movement. A sprain may further be characterized by edema, which is an abnormal accumulation of fluid in cells, tissues, or cavities of the body resulting in swelling.

A severe sprain may look and feel like a fracture, and it can be difficult for health professionals to tell the difference. A ligament rupture can occur at the midsubstance of the ligament or at the ligament-bone junction; sometimes an avulsion fracture also occurs, where the ligament pulls a piece of bone with it on injury.

Body Systems Involved

Sprains involve several interconnected biological systems:

• Musculoskeletal system: Ligaments are collagen fibers that connect bones together, providing passive stabilization to a joint. These fibers can be found in various organizational patterns depending on the function of the joint involved. Ligaments can be extra-capsular, capsular, or intra-articular.
• Inflammatory system: Acute inflammation is a response to any type of trauma, including that causing a sprain, wherein the inflammation protects the tissue and removes damaged material. Enzymatic signaling agents including histamine, serotonin, bradykinin, and prostaglandin are normally released as part of the inflammatory process. These agents increase capillary membrane permeability to enhance the inflammatory process but also result in edema from fluid accumulation. These signaling agents cause the primary symptoms of inflammation: swelling, heat, redness, and pain.
• Proprioceptive/neurological system: The ligament plays an important role in proprioceptive function, meaning sprain injuries can disrupt sensory feedback loops governing balance and joint position sense.
• Connective tissue/extracellular matrix: The healing of musculoskeletal tissues, such as bone, tendons, and ligaments, is dependent on the capacity of collagen synthesis and cross-linking. Poorly developed extracellular matrices derived from collagen can lead to inadequate tissue structures and biomechanical strength, which can result in unsatisfactory outcomes and an increased risk for reinjuries.
• Vascular system: Some ligaments have an outer layer called an epiligament, which has many more blood vessels and nerves than the inner part. It seems to play an important role in detecting and repairing injuries; blood vessels feed the tissues as they repair. Tendons and ligaments are made up of dense connective tissue primarily composed of collagen, and because they have a limited blood supply, their healing process is slower compared to muscles or skin.

Commonly Affected Joints

Any joint supported by ligaments can be sprained; the most commonly sprained joints include the ankle (including high ankle sprains). Sprains also typically occur in knees and wrists. For example, excessive inversion of the ankle can cause the lateral ankle ligaments — primarily the anterior talofibular ligament — to rupture. Wrist sprains commonly occur after a fall onto an outstretched hand (FOOSH).

Epidemiology

Ankle sprain represents one of the most common injuries sustained during sporting activities, accounting for 10% to 30% of single sport injuries. More than 50% of all injuries in sports can be classified as sprains, strains, ruptures, or breaks of musculoskeletal tissues. A review of emergency department records in the U.S. estimates the incidence rate of an ankle sprain to be 2.15 per 1,000 persons, with the highest age cohort being between the ages of 15 and 19 (7.2 per 1,000 person-years).

Females are at a higher risk of sustaining an ankle sprain compared with males, and children compared with adolescents and adults. The meta-analysis demonstrated a higher incidence of ankle sprain in females compared with males (13.6 vs 6.94 per 1,000 exposures), and in children compared with adolescents (2.85 vs 1.94 per 1,000 exposures), with adolescents having a higher rate than adults (1.94 vs 0.72 per 1,000 exposures). The sport category with the highest incidence of ankle sprain was indoor/court sports, with a cumulative incidence rate of 7 per 1,000 exposures.

Contributing and Associated Factors

Non-Modifiable Risk Factors

Non-modifiable risk factors associated with ankle sprain include gender, age, height, and previous ankle sprain, whereas modifiable risk factors include weight, BMI, postural stability, and exposure to sport. Previous ankle sprain injury (odds ratio = 2.74) is one of the most consistently identified risk factors in male athletes in systematic review and meta-analysis.

Modifiable Lifestyle and Biomechanical Factors

As a person ages, ligaments can start to weaken and become more likely to be injured. Body mass and balance impairment are modifiable contributors: higher body mass index, higher weight, lower isometric hip abduction strength, and lower dynamic balance performance have been identified as risk factors in systematic review and meta-analysis.

Nutritional and Metabolic Factors

Suboptimal nutritional status is a well-recognised risk factor for sports injury. Low energy availability (<30 kcal/kg fat-free mass/day) and deficiencies in several nutrients — calcium, iron, vitamin D, carbohydrate, protein — may predispose athletes to injury. Improper nutrition can elevate the risk for injury, delay recovery and rehabilitation after injury, and contribute to immune dysfunction.

It is crucial for bone, muscle, tendon, and ligament health to ensure there are no dietary deficiencies, especially low protein intake or inadequate vitamin C, vitamin D, copper, omega-3 polyunsaturated fatty acids, or calcium.

In a retrospective study of 867 orthopaedic trauma patients, nutritional deficiencies were found for prealbumin (50.5%), albumin (23.4%), and transferrin (48.5%). A high prevalence of micronutrient deficiencies was observed: vitamin A (35.4%), vitamin C (54.4%), vitamin D (75.4%), and zinc (56.5%).

The Healing Phases of Sprain Injury

Ligament healing proceeds through overlapping phases that are each nutritionally sensitive:

• Inflammatory phase: This initial phase of inflammation can start after one or two days and end after three or four days.
• Proliferative phase: New collagen fibers are laid down to rebuild the injured tissue during this phase, lasting up to several weeks.
• Remodeling phase: Collagen is reorganized to restore strength and function over weeks to months. Nutrition plays a key role in all three stages, supporting everything from reducing excessive inflammation to synthesizing new collagen.

Nutrients Studied or Traditionally Used in Relation to Sprains

Vitamin C (Ascorbic Acid)

Role in Connective Tissue

Vitamin C is an essential nutrient for humans, who are unable to synthesise it themselves. It is important for tissue regeneration due to the role it plays in collagen formation and its antioxidant properties. Vitamin C is a cofactor for collagen production and helps stabilize the collagen triple-helix structure; it also has antioxidant properties that protect healing tissues from oxidative stress. In the setting of vitamin C deficiency, collagen production is abnormal, leading to defective vessel and connective tissue formation with degradation of unstable collagen molecules.

Scientific Evidence

Preclinical studies demonstrated that vitamin C has the potential to accelerate bone healing after a fracture, increase type I collagen synthesis, and reduce oxidative stress parameters. The most important finding of this systematic review was that there is preclinical evidence that vitamin C supplementation accelerates bone healing after fractures, increases type I collagen synthesis, and reduces oxidative stress parameters. However, clinical evidence does not replicate the results seen in animal models to date. Furthermore, high doses (≥1,000 mg/day) of orally administered vitamin C had no direct benefit compared with controls.

All three preclinical studies evaluating oxidative stress reported that vitamin C was effective in reducing oxidative stress after injuries, signified by improved tissue composition in ligaments, tendons, and bone. No adverse effects were reported in either animal models or human participants; however, because of the limited number of human studies, further clinical investigations are needed before the implementation of vitamin C as a post-injury supplement.

Evidence strength: Preclinical evidence is promising; human clinical evidence is preliminary and weak. Vitamin C sufficiency is important for collagen integrity, but the benefit of supplementation above adequacy in humans with sprains specifically remains unestablished.

Vitamin C–Enriched Gelatin and Collagen Peptides

Scientific Evidence

A study was designed to determine whether gelatin supplementation could increase collagen synthesis. Eight healthy male subjects completed a randomized, double-blinded, crossover study in which they consumed either 5 or 15 g of vitamin C–enriched gelatin or a placebo control. Supplementation with increasing amounts of gelatin increased circulating glycine, proline, hydroxyproline, and hydroxylysine, peaking 1 hour after the supplement was given. Engineered ligaments treated with serum collected 1 hour after gelatin consumption showed increased collagen content and improved mechanics. Subjects who took 15 g gelatin 1 hour before exercise showed double the amino-terminal propeptide of collagen I in their blood, indicating increased collagen synthesis. These data suggest that adding gelatin to an intermittent exercise program improves collagen synthesis and could play a beneficial role in injury prevention and tissue repair.

One randomized, double-blind, crossover study showed that the combination of jumping exercise together with gelatin and vitamin C supplementation (15 g gelatin + 50 mg vitamin C) increased in vitro collagen production and a two-fold increase in amino-terminal propeptide of type I collagen in blood, which is indicative of increased collagen synthesis.

Evidence strength: Preliminary but mechanistically plausible. This is a small, short-term study in healthy men; direct applicability to sprain recovery in clinical populations requires further investigation.

Vitamin D

Role in Musculoskeletal Health

Despite some conflicting results, included studies showed that vitamin D regulates collagen synthesis, inflammation, and mineralization within tendons through its interaction with vitamin D receptors. Deficiency in vitamin D is a global health concern, affecting up to 77% of the population, with athletes being particularly susceptible due to high physical demands and potential limited sun exposure. Optimal levels of vitamin D are critical for musculoskeletal health, and insufficiency has been linked to muscle weakness, impaired neuromuscular function, and increased injury risk.

Scientific Evidence

Patients with ligamentous/cartilaginous injuries exhibited the highest percentage of low vitamin D (76.5%), followed by those with patellofemoral-related complaints (71.0%), muscle/tendon injuries (54.6%), and bone stress injuries (45.5%). One database study reports an association between patients previously diagnosed with hypovitaminosis D and significantly increased rates of both index ACL tears (81% increase within 2 years of diagnosis) and revision ACL reconstruction (28% within 2 years).

Most studies reported that low vitamin D levels were associated with a significantly increased risk of ACL injuries and poorer postoperative muscle strength recovery. However, evidence regarding bone health and functional outcomes was inconsistent. Qualitative synthesis indicated a potential protective role of vitamin D in ACL recovery, but limitations include a high risk of bias and inconsistent evidence on functional outcomes, underscoring the need for further research.

Evidence strength: Observational associations are notable, but causal relationships are not established due to the absence of RCTs. Evidence is Level III (observational). Deficiency correction is well-supported; supplementation beyond sufficiency lacks clinical trial evidence in sprain-specific contexts.

Protein and Amino Acids

Role in Connective Tissue Repair

Protein is the foundation of tissue repair. Amino acids like glycine, proline, and lysine are essential for collagen synthesis. A diet lacking in protein can significantly delay healing. Nutritional strategies that benefit the rehabilitation process in injured athletes include balanced energy intake and a high-protein and carbohydrate-rich diet; supportive supervision should be provided to avoid low energy availability.

Scientific Evidence

The potential of supplementation with collagen, creatine monohydrate, omega-3 (fish oils), and vitamin D requires further research, although the effects are quite promising. It is worth noting the lack of clinical research in injured athletes and the higher number of reviews in the last 10 years.

Evidence strength: Adequate protein intake is broadly supported by nutrition science for tissue repair; specific dosing strategies for ligament sprains remain underexplored in high-quality clinical trials.

Omega-3 Polyunsaturated Fatty Acids

Role in Inflammation and Healing

Considering the lack of clear evidence to establish guidelines for the intake of fatty acids in athletes when the aim is to prevent or assist in the treatment of muscle injury, it is considered more prudent to recommend that the athlete's diet maintains a low omega-6/omega-3 ratio.

Scientific Evidence

Eight weeks of omega-3 PUFA supplementation (daily providing 1,530 mg of EPA and 1,035 mg of DHA) was found to have a modest improvement on disability and pain outcomes in one randomized controlled trial on rotator cuff-related shoulder pain. Direct RCT evidence in ligament sprain specifically is limited.

Evidence strength: Mechanistic plausibility is well-established; modest clinical evidence exists for related connective tissue conditions. Evidence specific to ligament sprains is preliminary.

Zinc

Role in Healing

Zinc plays a critical role in tissue regeneration, immune response, and collagen synthesis; even a mild deficiency can impair healing. In a study of orthopaedic trauma patients, zinc deficiency was observed in 56.5% of the population studied, representing the most prevalent micronutrient deficiency alongside vitamin D.

Evidence strength: The importance of zinc sufficiency for wound healing and collagen synthesis is established in the broader literature. Specific intervention trials in sprain recovery are lacking; evidence is largely indirect.

Herbs and Botanical Ingredients Studied in Relation to Sprains

Arnica montana

Traditional Use

Arnica montana has been used as a remedy for centuries, and is common today for the treatment of pain, swelling, and bruises. A combination product with arnica tincture (aqueous-ethanolic extract from the flowers of Arnica montana) has a long history of clinical use in ankle joint distortion in Germany and the Czech Republic. Topical anti-inflammatory and analgesic properties of preparations from arnica flowers are amply described in monographs; flavonoids and sesquiterpene lactones of the helenalin type are generally held responsible for the observed effects.

Scientific Evidence

Eleven controlled trials were found, five in volunteers and six in patients, examining topical arnica. Heterogeneity in health conditions, arnica dosage, co-interventions, and effects measurements was high, and many studies had important methodological flaws. The efficacy of arnica in doses of 10% and below is not supported by the available evidence, and more research is needed to determine if higher doses would be effective and remain safe.

Eight trials examining homeopathic arnica fulfilled inclusion criteria; most related to conditions associated with tissue trauma. Most of these studies were burdened with severe methodological flaws. On balance, they do not suggest that homeopathic arnica is more efficacious than placebo.

Arnica shows different biological activities in laboratory research, including antioxidant, anti-inflammatory, antibacterial, antifungal, and antitumor effects; arnica formulations are mainly used for pain management.

Evidence strength: Traditional use is long-established in European phytomedicine. Clinical trial evidence for topical phytotherapeutic (not homeopathic) formulations is mixed and limited by methodological issues. The evidence base does not currently support firm efficacy conclusions for doses at or below 10%.

Bromelain (from Ananas comosus)

Traditional and Historical Use

Pineapple (Ananas comosus) is a well-known tropical plant that has been used for centuries for both its medicinal purposes and its food value. Bromelain is a complex chemical found in the aqueous extract of the pineapple and is composed largely of proteolytic enzymes. As an individual product, bromelain has been available commercially since 1957.

Mechanisms

Bromelain is a proteolytic enzyme derived from the stem of the pineapple plant as a complex mixture of different thiol-endopeptidases, phosphatases, glucosidases, peroxidases, cellulases, glycoproteins, and carbohydrates. Bromelain directly affects pain mediators such as bradykinin, decreases swelling and bruising, and shortens the healing period following trauma and surgical procedures. Bromelain also reduces plasma kininogen, thus inhibiting the production of kinin, which is known as an agent that induces inflammation, pain, and swelling.

Bromelain decreases the release of IL-1β, IL-6, and TNF-α, as immune cells involved in inflammation-induced cytokine generation are affected. By blocking the T cell signal transduction pathway, bromelain can inhibit the Raf-1/extracellular-regulated-kinase-(ERK-)2 pathways.

Scientific Evidence

A small number of studies have been done on the use of bromelain taken orally for reducing symptoms of sinusitis and reducing pain and swelling after wisdom tooth extraction. Bromelain has been shown to produce both analgesic and anti-inflammatory effects in patients with rheumatoid arthritis when taken orally. Direct high-quality RCT evidence specifically in ligament sprains is limited.

Taken orally, bromelain acts to block prostaglandin synthesis, thereby reducing the nociceptive perception of pain. Bromelain is well tolerated by the gastrointestinal system, and animal studies have shown that it has no toxic effect up to 10 g/kg body weight.

Evidence strength: Mechanistic and in vitro data are substantial; bromelain's anti-inflammatory and analgesic properties are well characterised in laboratory and some surgical settings. Clinical trials specifically in ligament sprain populations are lacking. Existing evidence is preliminary and largely indirect.

Curcumin (from Curcuma longa — Turmeric)

Traditional Use

Turmeric (Curcuma longa) has been used for centuries in Ayurvedic and traditional Chinese medicine as an anti-inflammatory remedy applied topically or consumed as a spice in therapeutic preparations for joint pain, swelling, and soft tissue injury.

Scientific Evidence

Curcumin is a natural compound for which current studies have shown good anti-inflammatory, immunosuppressive, and anticancer properties. Evidence from multiple clinical trial studies suggests that curcumin can reduce the subjective experience of pain in patients with system-related disorders of muscle disease. The preponderance of clinical trial evidence relates to osteoarthritis and chronic joint conditions rather than acute ligament sprains.

Evidence strength: Substantial laboratory evidence for anti-inflammatory mechanisms; clinical trial evidence is predominantly in arthritis and chronic musculoskeletal pain. Evidence specific to acute sprains is absent from high-quality trials. Bioavailability of standard curcumin preparations is low, which is a noted limitation in clinical translation.

Dietary and Lifestyle Factors Discussed in Authoritative Sources

Overall Nutritional Status and Energy Availability

Low energy availability (<30 kcal/kg fat-free mass/day) and deficiencies in several nutrients (calcium, iron, vitamin D, carbohydrate, protein) may predispose athletes to injury. Nutritional strategies that benefit the rehabilitation process in injured athletes include balanced energy intake and a high-protein and carbohydrate-rich diet; supportive supervision should be provided to avoid low energy availability.

Protein Intake

Protein is the foundation of tissue repair. Amino acids like glycine, proline, and lysine are essential for collagen synthesis. A diet lacking in protein can significantly delay healing.

Anti-Inflammatory Dietary Patterns

Considering the lack of clear evidence for guidelines on fatty acid intake in athletes for injury prevention, it is considered more prudent to recommend that the athlete's diet maintains a low omega-6/omega-3 ratio. A diet rich in whole foods, vegetables, and sources of omega-3 fatty acids is consistently discussed in the sports nutrition literature as supportive of reducing the chronic low-grade inflammation that may impair tissue integrity.

Micronutrient Adequacy

It is crucial for bone, muscle, tendon, and ligament health to ensure that there are no dietary deficiencies, especially low protein intake or inadequate vitamin C, vitamin D, copper, omega-3 PUFA, or calcium.

Body Weight and Composition

Higher BMI and higher weight have been identified as significant risk factors for ankle sprain in systematic review and meta-analysis. Maintaining a healthy body weight through diet is therefore considered a modifiable contributor to sprain risk in the literature.

Hydration

Adequate hydration supports the maintenance of synovial fluid in joint capsules and the viscoelastic properties of ligamentous tissue, though direct clinical trial evidence specifically linking hydration to sprain incidence or recovery is limited in the peer-reviewed literature.

Physical Activity and Exercise

Most ligament injuries are accidents, but exercise can help keep ligaments strong and less prone to injury. Nutritional and/or exercise interventions that increase collagen synthesis and strengthen these tissues could have an important effect on injury rates.

Sleep and Stress

Other lifestyle factors including poor sleep, psychological stress, and long-haul travel can also contribute to depressed immune function, which in turn may influence the capacity for tissue repair following injury.

Summary of Evidence Levels

• Vitamin C (sufficiency): Essential for collagen synthesis; deficiency clearly impairs healing. Supplementation above sufficiency — preliminary human evidence, not yet established for sprains specifically.
• Vitamin C–enriched gelatin/collagen peptides: Small human RCT demonstrates increased collagen synthesis biomarkers; preliminary, requires replication in larger clinical populations.
• Vitamin D (sufficiency): Observational associations between deficiency and increased ligament injury risk are notable; no RCTs in sprain-specific prevention. Correction of deficiency broadly supported.
• Protein and amino acids: Broadly supported for tissue repair by nutritional science; sprain-specific dosing evidence limited.
• Omega-3 fatty acids: Modest clinical evidence in related connective tissue disorders; direct sprain-specific evidence is preliminary.
• Zinc: High prevalence of deficiency in orthopaedic trauma patients; essential for collagen synthesis and healing, but sprain-specific intervention trials lacking.
• Arnica montana (topical phytotherapeutic): Long traditional use in European herbal medicine; clinical trial evidence mixed and methodologically limited; efficacy at doses ≤10% not established.
• Bromelain: Mechanistically well-characterised; clinical evidence mostly in surgical and dental settings; sprain-specific RCTs lacking.
• Curcumin/turmeric: Anti-inflammatory mechanisms well-described; clinical trials mostly in arthritis; no high-quality evidence specific to acute sprains.

References

• Cleveland Clinic — Sprains: Types, Symptoms & Treatment
• Cleveland Clinic — Ligament: What It Is, Anatomy & Function
• Physiopedia — Ligament Sprain
• ScienceDirect Topics — Sprain Overview
• Wikipedia — Sprain
• Harvard Health — Sprain Overview A to Z
• Doherty et al. — The Incidence and Prevalence of Ankle Sprain Injury: A Systematic Review and Meta-Analysis (Sports Medicine, 2014)
• Intrinsic Risk Factors for Ankle Sprain Differ Between Male and Female Athletes: A Systematic Review and Meta-Analysis (PMC, 2022)
• Lower Extremity Review — Sprain in the Forecast: Epidemiology and Risk Factors for Ankle Sprain
• International Journal of Sport Nutrition and Exercise Metabolism — Nutrition for the Prevention and Treatment of Injuries in Track and Field Athletes (2019)
• ScienceDirect — Nutrition for Optimising Immune Function and Recovery from Injury in Sports (2025)
• PMC — Nutrition and Vitamin Deficiencies Are Common in Orthopaedic Trauma Patients
• DePhillipo et al. — Efficacy of Vitamin C Supplementation on Collagen Synthesis and Oxidative Stress After Musculoskeletal Injuries: A Systematic Review (Orthopaedic Journal of Sports Medicine, 2018)
• PMC — A Systematic Review on the Role of Vitamin C in Tissue Healing (2022)
• Shaw et al. — Vitamin C–Enriched Gelatin Supplementation Before Intermittent Activity Augments Collagen Synthesis (American Journal of Clinical Nutrition, 2017)
• PMC — Effect of Vitamin D on Anterior Cruciate Ligament Injury Rates and Post-Reconstruction Function: A Systematic Review (2025)
• PMC — Prevalence of Vitamin D Insufficiency and Deficiency in Young, Female Patients With Lower Extremity Musculoskeletal Complaints
• ScienceDirect — A Diagnosis of Vitamin D Deficiency Is Associated With Increased Rates of Anterior Cruciate Ligament Tears and Reconstruction Failure
• PMC — Nutritional Strategies in the Rehabilitation of Musculoskeletal Injuries in Athletes: A Systematic Integrative Review (2023)
• Journal of the International Society of Sports Nutrition — The Impact of Nutrition on Tendon Health and Tendinopathy: A Systematic Review (2022)
• Plants (MDPI) — Effects of Arnica Phytotherapeutic and Homeopathic Formulations on Traumatic Injuries and Inflammatory Conditions: A Systematic Review (2024)
• PMC — Arnica/Hydroxyethyl Salicylate Combination Spray for Ankle Distortion: A Four-Arm Randomised Double-Blind Study
• Brito et al. — Systematic Review on the Efficacy of Topical Arnica montana for the Treatment of Pain, Swelling and Bruises (2014)
• NIH NCCIH — Bromelain: Usefulness and Safety
• PMC — Bromelain, a Group of Pineapple Proteolytic Complex Enzymes and Their Possible Therapeutic and Clinical Effects (2021)
• PMC — Effect of Oral Bromelain on Wound Healing, Pain, and Bleeding at Donor Site Following Free Gingival Grafting: A Clinical Trial
• PMC — Efficacy and Safety of Curcumin and Curcuma longa Extract in the Treatment of Arthritis: A Systematic Review and Meta-Analysis (2022)
• PMC — Nutritional Indicators of Bone Nonunion: A Systematic Review (2024)