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Watermelon juice concentrate

Also known as: Watermelon juice concentrate, Watermelon extract, Watermelon powder, Citrullus lanatus

Overview

Watermelon juice concentrate is a functional food ingredient derived from the fruit *Citrullus lanatus*. It is rich in bioactive compounds, notably the amino acids L-citrulline and L-arginine, and the antioxidant lycopene. This concentrate is primarily used as a dietary supplement for its potential benefits in cardiovascular health, particularly blood pressure regulation and vascular function, and for aiding muscle soreness recovery in athletes. It is characterized by its high content of these beneficial amino acids and antioxidants, along with natural sugars. While research on watermelon juice concentrate is ongoing, several randomized controlled trials and meta-analyses support its efficacy for certain applications, though long-term clinical outcomes are still being investigated. It is commonly consumed as a juice or in various supplement forms.

Benefits

Watermelon juice concentrate offers several evidence-based benefits, primarily due to its L-citrulline and lycopene content: 1. **Cardiovascular Health (Blood Pressure & Lipids):** A meta-analysis of 9 randomized controlled trials demonstrated significant reductions in systolic blood pressure (SBP), total cholesterol, and LDL cholesterol following watermelon supplementation. These improvements are considered clinically relevant, indicating its potential role in managing cardiovascular risk factors. The effects on blood pressure are more pronounced in hypertensive or at-risk populations compared to healthy individuals. 2. **Exercise Recovery:** Small-scale randomized controlled trials suggest that L-citrulline from watermelon juice can improve post-exercise muscle soreness and reduce recovery heart rate in athletes. This benefit is attributed to improved blood flow and nitric oxide-mediated effects, aiding in faster recovery. 3. **Antioxidant Support:** Watermelon juice concentrate is a source of lycopene, a potent antioxidant. Studies show that consumption significantly increases circulating lycopene levels, which can help reduce oxidative stress in vascular tissues. While direct effects on vascular function in healthy individuals have been mixed, the antioxidant properties contribute to overall vascular health. While some studies noted a slight, non-clinically significant increase in fasting blood sugar, no significant effects on diastolic blood pressure, heart rate, BMI, or inflammation markers (CRP) have been consistently observed. The benefits, particularly for blood pressure and lipids, typically manifest within weeks of consistent supplementation.

How it works

The primary mechanism of action for watermelon juice concentrate revolves around its L-citrulline content. L-citrulline is readily converted to L-arginine in the body, which is a crucial precursor for the synthesis of nitric oxide (NO). NO is a potent vasodilator, meaning it helps relax and widen blood vessels, thereby improving blood flow and reducing blood pressure. This process enhances endothelial function, which is vital for cardiovascular health. Additionally, lycopene, another key compound in watermelon, acts as a powerful antioxidant, reducing oxidative stress and inflammation within the vascular system. These combined actions contribute to improved cardiovascular function and may also aid in muscle recovery by enhancing blood flow to fatigued muscles.

Side effects

Watermelon juice concentrate is generally considered safe, with no serious adverse effects reported in clinical trials. The most commonly observed side effect, though not clinically significant, is a slight increase in fasting blood glucose levels. This effect has been noted in some studies but typically remains within a normal range and does not pose a significant concern for most individuals. There are no well-documented drug interactions, but caution is advised for individuals already taking antihypertensive medications, as watermelon juice concentrate could potentially have an additive blood pressure-lowering effect. While no formal contraindications are established, individuals with diabetes should monitor their blood glucose levels if consuming watermelon juice concentrate regularly due to the potential for a slight increase. Data on its safety in pregnant or lactating women is limited, and effects may vary based on age and overall health status.

Dosage

The optimal dosage for watermelon juice concentrate varies depending on the intended benefit and the concentration of the product. For cardiovascular benefits, studies have typically used approximately two 360 mL servings of 100% watermelon juice daily, totaling around 720 mL. This corresponds to L-citrulline doses ranging from approximately 1.17 g to 6 g. For muscle recovery in athletes, similar L-citrulline doses from watermelon juice have been used, with consumption before or after exercise potentially being beneficial. The maximum safe dose is not precisely defined, but doses up to 6 g of L-citrulline from watermelon juice have been shown to be safe in short-term studies. It is important to note that fresh or unpasteurized juice is preferred, as heat treatment (pasteurization) can reduce the bioavailability of L-citrulline.

FAQs

Is watermelon juice concentrate effective for blood pressure?

Yes, meta-analyses support a modest reduction in systolic blood pressure, particularly in hypertensive or at-risk populations. Effects may vary among individuals.

Does it improve vascular function in healthy adults?

Evidence is mixed. Some studies show no significant effect in healthy postmenopausal women, while benefits have been observed in hypertensive or younger adults.

Can it reduce muscle soreness?

Yes, small studies indicate that watermelon juice can reduce muscle soreness and improve recovery heart rate in athletes, likely due to its L-citrulline content.

Is it safe for long-term use?

Short-term studies show it is generally safe with no serious adverse effects. Long-term data are limited, but no major safety concerns have been reported.

Should diabetics avoid it due to glucose increase?

A slight, non-clinically significant increase in fasting glucose has been observed. Diabetics should monitor their blood glucose levels if consuming it regularly.

Research Sources

https://pmc.ncbi.nlm.nih.gov/articles/PMC8435004/ – This double-blind, placebo-controlled crossover RCT with 21 healthy postmenopausal women found that 4 weeks of watermelon juice supplementation increased circulating lycopene but did not significantly improve vascular function. A slight, non-clinically significant increase in fasting glucose was observed.
https://pubmed.ncbi.nlm.nih.gov/37369281/ – This systematic review and meta-analysis of 9 RCTs (with ≥30 participants per group) concluded that watermelon supplementation significantly reduced systolic blood pressure, total cholesterol, and LDL cholesterol. It also noted a slight increase in fasting blood sugar but no significant effects on diastolic blood pressure, heart rate, or BMI.
https://pubs.acs.org/doi/abs/10.1021/jf400964r – This small pilot RCT with 7 athletes found that watermelon juice reduced muscle soreness and recovery heart rate after exercise. It also suggested that L-citrulline bioavailability is higher in fresh, unpasteurized watermelon juice compared to heat-treated forms.
https://pmc.ncbi.nlm.nih.gov/articles/PMC9592950/ – This meta-analysis of RCTs focused on L-citrulline, showing that watermelon consumption significantly increases postprandial L-citrulline and L-arginine levels. While it did not directly assess clinical endpoints, it supports the bioavailability of these amino acids from watermelon.