How dietary zinc affects your chances of having a stroke

How dietary zinc affects your chances of having a stroke

New research suggests that consuming zinc in a specific range may reduce stroke risk, but more is not always better, highlighting the importance of targeted nutrition for brain health.

Study:Dietary zinc intake associated with stroke in American adults– Photo credit: Evan Lorne/Shutterstock.com

A study recently published in the journalScientific reportsexamined the relationship between dietary zinc intake and stroke prevalence in adults.

What is a stroke?

Stroke occurs when blood flow to the brain is disrupted. There are two main types of stroke: ischemic stroke (IS) and hemorrhagic stroke. It occurs when blood flow to the brain is blocked while hemorrhagic stroke is caused by bleeding in or around the brain.

Previous studies have identified stroke as the second leading cause of death worldwide. It is also the third leading cause of disability, significantly increasing the socioeconomic burden, especially during treatment. Lifestyle-based interventions, including dietary changes and physical activity, can potentially prevent and reduce stroke risk. It is essential to identify the role of specific nutrients associated with stroke risk. This information would positively help clinicians to manage stroke incidence more efficiently.

Biological functions of zinc

Zinc is a trace mineral with antioxidant and anti-inflammatory properties. It is involved in many biological functions including cellular metabolism, cell proliferation, membrane stability and the regulation of oxidative stress. Zinc also acts as a cofactor for antioxidant enzymes.

Several studies have shown that zinc deficiency is associated with chronic diseases such as diabetes, hypertension, seizures, Alzheimer's disease, cardiovascular disease (CVD), and depression. These studies have also shown that stroke patients are more susceptible to lower serum zinc levels than healthy individuals.

Some results suggest that they may benefit from zinc supplements to support neurological recovery after a stroke. However, further research is needed to confirm this.

Understanding the precise relationship between zinc consumption and stroke prevalence is crucial.

About the study

The current study uses National Health and Nutrition Examination Survey (NHANES) data to conduct a cross-sectional analysis examining the potential relationship between zinc intake and stroke prevalence. The authors hypothesized that individuals with a history of stroke have lower dietary zinc intakes compared to the general population.

The NHANES dataset includes multiple cross-sectional, continuous, stratified probability surveys of noninstitutionalized Americans. Medical Illness Questionnaire (MCQ) was used to detect stroke. The Computer-Assisted Dietary Interview (CADI) system was used to accurately estimate dietary content based on individual food and beverage consumption using the US Department of Agriculture automated multiple pass method (AMPM).

The present study included individuals aged 18 years or older who participated in four 2-year NHANES study cycles from 2013 to 2020. The average zinc intake of the selected candidates was assessed using NHANES dietary data. Three multivariable logistic regression models assessed the relationships between dietary zinc consumption and stroke. Model 1 was adjusted for sociodemographic variables and Model 2 was adjusted for all variables in Model 1 along with smoking status, BMI, and energy expenditure. Model 3 included all variables from Model 2 in addition to diabetes, coronary heart disease, hypertension, hypercholesterolemia, antihypertensive drug use, and prophylactic aspirin use.

Study results

A total of 2,642 participants met the eligibility criteria for the current cross-sectional study. Participants were divided into four quartiles (Q1–Q4) according to their dietary zinc intake levels: less than 6.08 mg/day (Q1), between 6.09 and 8.83 mg/day (Q2), between 8.84 and 13.02 mg/day (Q3), and more than 13.03 mg/day (Q4).

The average age of the study cohort was 62.8 years, with 53.7% of participants being female. Increased zinc consumption was associated with those with higher levels of education, being married or cohabiting, belonging to younger age groups, having middle class income, having lower smoking rates, having non-Hispanic white ethnicity, having higher energy expenditure, and having a higher body mass index (BMI). The group of people who showed increased zinc consumption consisted mainly of men.

Univariate analysis found that several factors were significantly associated with stroke, including age, higher family income, marital status, diabetes, non-Hispanic black ethnicity, coronary heart disease, smoking history, BMI, hypercholesterolemia, and medications.

In a multivariable analysis, an inverse association between dietary zinc intake and stroke was observed. After adjusting for potential confounders, people belonging to Q2 showed a significant decrease in the odds of stroke compared to those belonging to Q2. Restricted cubic spline analysis (RCS) revealed an L-shaped association between zinc intake and stroke severity.

Individuals consuming zinc at less than 8.82 mg per day showed an odd ratio (OR) for stroke prevalence of 0.858. The current study found that among people consuming less than 8.82 mg/day of zinc, each additional mg of zinc intake per day was associated with a 14.2% lower chance of stroke. However, this association was only observed in people who consumed less than 8.82 mg/day. Higher intake beyond this threshold showed no further reduction in the likelihood of stroke.

These results apply specifically to American adults. The study also found that many, particularly women, did not meet the recommended daily zinc intake.

The study also noted that it did not differentiate between ischemic and hemorrhagic stroke types, limiting the specificity of the results.

The authors acknowledge limitations, including reliance on self-reported stroke diagnosis and dietary outcome data, which may introduce recall or misclassification bias, and note that remaining confounding from unmeasured variables cannot be excluded due to the cross-sectional study design.

Conclusions

The current study found that dietary zinc intake within a certain range was associated with reduced stroke prevalence. Furthermore, increasing zinc intake did not appear to produce further protective effects.

Further research, including randomized controlled trials, is needed to assess whether increasing dietary zinc intake can effectively reduce the risk of stroke.

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