Abstract
Objective—Prospective data are scarce on the relation of red meat, seafood, and poultry consumption with hypertension risk. Although red and processed meats are generally considered to have adverse cardiovascular consequences, seafood is believed to be protective and poultry’s effect is controversial. Methods—We prospectively examined the independent association of long-term intake of animal flesh with incident hypertension in three longitudinal cohort studies of non-hypertensive individuals: Nurses’ Health Study I (NHS I, n=62,273 women), Nurses’ Health Study II (NHS II, n=88,831 women), and Health Professionals Follow-up Study (HPFS, n=37,414 men). We used multivariable Cox proportional hazards regression to study the associations of different types of animal flesh with the risk of developing hypertension while controlling for other hypertension risk factors. We then used fixed effects meta-analysis to derive pooled estimates of effect. Results—Compared with participants whose consumption was <1 serving/month, the pooled hazard ratios (HR) among those whose intake was ≥1 serving/day were 1.30 (95% CI: 1.23-1.39) for total meat (a combination of processed and unprocessed red meat), 1.22 (1.12-1.34) for poultry, and 1.05 (0.98-1.13) for seafood. Seafood was associated with an increased risk of hypertension in HPFS and NHS II, but not NHS I. Consumption of any animal flesh ≥1 serving/day was associated with an increased hypertension risk (pooled HR=1.30 [1.16-1.47]). Conclusions—Long-term intake of meat and poultry were associated with increased risk of hypertension. In contrast to our hypothesis, we found a weak but significant trend towards an increased risk of hypertension with increasing seafood consumption.
Generated Summary
This research article investigates the association between long-term intake of animal flesh (red meat, seafood, and poultry) and the risk of developing hypertension. The study employs a prospective cohort design, examining data from three large cohorts of non-hypertensive individuals: Nurses’ Health Study I (NHS I), Nurses’ Health Study II (NHS II), and Health Professionals Follow-up Study (HPFS). The primary objective is to determine the independent association of different types of animal flesh consumption with the incidence of hypertension while considering other hypertension risk factors. The research utilizes multivariable Cox proportional hazards regression to study these associations, followed by fixed-effects meta-analysis to derive pooled estimates of effect. The study’s approach involves analyzing dietary intake data collected over several years and assessing the relationship between consumption levels and the development of hypertension. The findings contribute to the existing body of knowledge on the dietary factors influencing hypertension risk.
Key Findings & Statistics
- Compared to participants whose consumption was <1 serving/month, the pooled hazard ratios (HR) among those whose intake was ≥1 serving/day were:
- 1.30 (95% CI: 1.23-1.39) for total meat (combination of processed and unprocessed red meat).
- 1.22 (1.12-1.34) for poultry.
- 1.05 (0.98-1.13) for seafood.
- Eating any animal flesh once per day or more was associated with a 30% higher risk of hypertension when compared with eating animal flesh less than once a month (HR=1.30, 1.16-1.47; p-trend<0.001).
- In young women (NHS II), higher intake of any type of animal flesh was independently related to an increased risk of hypertension.
- In NHS I, higher intakes of unprocessed red meat and total meat were associated with an increased risk of hypertension, but processed meat, poultry, and seafood were not associated with hypertension.
- In men (HPFS), greater poultry consumption and greater seafood consumption were independently related with increased hypertension risk, and there was no association with higher consumption of processed meat.
- When the intake of various types of flesh were analyzed as continuous variables, the pooled HRs for hypertension associated with one additional serving per day were:
- 1.04 (1.01-1.07) for processed meat.
- 1.09 (1.06-1.11) for unprocessed red meat.
- 1.07 (1.03-1.10) for poultry.
- 1.09 (1.06-1.13) for seafood.
- The associations of animal flesh intake with hypertension were overall similar when all types of flesh intake were included simultaneously in the same multivariable model. Specifically, comparing the highest (≥1 serving/day) with the lowest (<1 serving/month) categories of intake, the pooled HRs were 1.03 (0.97-1.09) for processed meat, 1.21 (1.14-1.29) for unprocessed red meat, 1.12 (1.02-1.23) for poultry, and 1.05 (0.98-1.14) for seafood.
- Replacing one serving of total (processed and unprocessed) meat or poultry with one serving seafood was associated with an increased risk of developing hypertension in HPFS (HR=1.12 [1.05-1.18] and HR= 1.09 [1.00-.1.20], respectively).
- During 2,936,359 person-years of follow-up, 78,208 participants reported a new diagnosis of hypertension (35,777 cases/1,043,941 person-years in NHS I, 25,843 cases/1,396,062 person-years in NHS II, and 16,855 cases/564,247 person-years in HPFS).
Other Important Findings
- The study found that long-term intake of meat and poultry were associated with an increased risk of hypertension.
- A weak but significant trend towards an increased risk of hypertension with increasing seafood consumption was also observed.
- In the secondary analysis, moderate intakes of canned tuna and dark meat fish (4-6 servings a week) were independently associated with a higher risk of hypertension.
- The test of heterogeneity among the three cohorts was significant for the associations of poultry (P for heterogeneity of 0.03), total meat (P<0.001) and animal flesh (P<0.001).
- Adjusting for sodium intake revealed similar results, so did the inclusion of other micronutrients into our model, such as potassium, calcium, magnesium, and fiber.
- There were no consistent interactions between any type of flesh intake and either age or BMI as pertains to hypertension risk.
- Adjusting for the DASH diet score did not materially alter our findings (data not shown).
Limitations Noted in the Document
- The diagnosis of hypertension was self-reported, without direct measurement of blood pressures.
- Dietary intake categorization may be subject to misclassification due to imperfect dietary data acquisition via FFQs and seasonal diet variations not captured by the FFQ.
- Residual confounding may be present, despite controlling for numerous hypertension risk factors.
- Heterogeneity in findings existed among the three cohorts.
- The study participants were predominantly non-Hispanic white men and women.
Conclusion
The study’s findings suggest a significant association between higher animal flesh intake and an increased risk of developing hypertension. The researchers noted, “Long-term intake of meat and poultry were associated with increased risk of hypertension. In contrast to our hypothesis, we found a weak but significant trend towards an increased risk of hypertension with increasing seafood consumption.” The study provides data that underscore the importance of dietary choices in managing hypertension risk. It aligns with other studies that suggest a link between meat consumption and cardiovascular issues and potentially highlights that long-term avoidance of meat may reduce the risk of developing hypertension. The results of our substitution analyses are summarized in Figure 1. Replacing one serving of total (processed and unprocessed) meat or poultry with one serving seafood was associated with an increased risk of developing hypertension in HPFS (HR=1.12 [1.05-1.18] and HR= 1.09 [1.00-.1.20], respectively). Replacing one serving of total (processed and unprocessed) meat with one serving of seafood was not associated with hypertension in the female cohorts, and no other substitution analyses yielded significant findings. The observed increased risk of hypertension with greater seafood consumption might be limited to certain types of seafood, specifically canned tuna and dark meat fish.