Health-Promoting Effects of Goji Berries (Lycium barbarum): A Literature Overview ^†

Abstract

This literature overview examines the findings of meta-analyses investigating the health impacts of Goji berries and their derivatives. The aim was to provide a synthesis of available evidence regarding the potential benefits of Goji berries in various health parameters. A literature search (conducted in April 2024) yielded 1288 research items, from which five meta-analyses met the inclusion criteria. The included studies varied in the number of clinical trials, ranging from 4 to 10, with participant numbers spanning from 161 to 548. Participants predominantly comprised healthy individuals or those with metabolic disorders. Goji berries were administered orally in forms such as fruit juice, dried products (up to 90 g/day), or polysaccharide extracts, with dosages ranging from 120 mL daily for juice to 150–300 mg daily for polysaccharide extracts. Intervention durations varied from 2 weeks to 3 months. Results indicated favorable effects of Goji berries and their derivatives on lipid profile (elevation of HDL cholesterol levels by approximately 10–15 mg/dL), glucose metabolism (reduction of fasting glucose concentrations by around 7–6 mg/dL), oxidative stress, and quality of life, including an anti-fatigue effect. However, no significant effects were observed on body weight or blood pressure. In conclusion, this review suggests that Goji berries may offer potential health benefits, particularly in improving lipid and glucose metabolism, and reducing oxidative stress. However, further research is warranted to elucidate the full extent of their effects, ensuring evidence-based recommendations for clinical practice. Standardization of study methodologies and adherence to reporting guidelines are crucial for advancing knowledge in this field.

1. Introduction

Goji berries, also known as Lycium barbarum or wolfberries, are small, red-orange fruits native to Asia and have long been esteemed for their potential health benefits [1]. Rich in essential nutrients, including vitamins, minerals, and antioxidants, these berries have garnered considerable scientific interest in recent years, reaching the status of “superfood”. With a nutrient profile that includes polysaccharides [2], as well as high levels of vitamin C, carotenoids, minerals, phenolic compounds, and fiber [3], Goji berries are often consumed for their purported ability to boost immune function, improve vision, and promote overall well-being [4]. Despite their centuries-old traditional use in Chinese medicine, contemporary research has aimed to elucidate the specific mechanisms underlying these health effects [1,5].

The aim of this review is to evaluate the evidence from meta-analyses concerning the purported beneficial properties of Goji berries and their derivatives on various health parameters.

2. Methods

This study serves as an overview of meta-analyses, with its methods outlined here in accordance with a simplified version of PRISMA guidelines [6]. Meta-analyses considered for inclusion were required to be published in peer-reviewed journals and to provide a pooled estimate of the impact of Goji berries and their derivatives on health parameters. Relevant studies were also required to be in English or have a summary available in English. The inclusion criteria were as follows:

• Population (P): healthy individuals or patients diagnosed with any disease according to internationally recognized clinical standards.
• Intervention (I): consumption of Goji berries and their derivatives (such as fruit juice, dried products, and phytotherapeutic extracts containing polysaccharides) for any duration.
• Comparison (C): no consumption of Goji berries and their derivatives.
• Outcomes (O): any health-related parameter, including changes in metabolic indices, vital signs, body weight, oxidative stress status, and quality of life.
• Study design (S): meta-analyses of clinical studies.

A systematic search of PubMed was conducted for relevant meta-analyses up to April 2024, using the search terms “Goji Berry”, “Goji Berries”, “Lycium barbarum”, and “Wolfberry” in titles or abstracts. One author (M.A.) screened all retrieved research items, with a second check performed by another author (D.D.) for reproducibility. Data were collected and manually extracted by M.A. using an Excel spreadsheet. Any disagreements between the authors were resolved through discussion. The following data were extracted from eligible studies: sample size (number of studies and participants), intervention characteristics, duration of patient follow-up, major study endpoints, publication year, and main results of each meta-analysis.

To assess the quality of included meta-analyses, adherence to internationally recognized methodological criteria such as PRISMA or MOOSE guidelines, recommended by the EQUATOR network [7], was checked. PRISMA guidelines provide a checklist for reporting systematic reviews and meta-analyses of clinical trials, while MOOSE criteria offer evidence-based methods for designing meta-analyses of observational studies. The most significant findings from the included studies are summarized in a table and qualitatively discussed in subsequent sections of the article.

3. Results

After searching PubMed for relevant studies, 1288 research items were retrieved and five meta-analyses were deemed eligible for inclusion in this literature overview [8,9,10,11,12].

Table 1. Summary of quantitative evidence about the health benefits of Goji berry (Lycium barbarum) consumption.

Studies (Sample Size)—Population	Intervention: Goji Berries	Health Outcomes	Pooled Analysis	Review Guidelines	Year	Ref.
4 studies (n = 161)—healthy subjects	- Fruit juice: 120 mL/day for 0.5–1 month	Fatigue	OR = 3.51 [95% CI: 1.45; 8.48] (*)	-	2012	[8]
		Dizziness	OR = 2.65 [95% CI: 1.15; 6.12] (*)
		Sleep	OR = 3.23 [95% CI: 1.23; 8.47] (*)
7 studies (n = 548)—healthy subjects or patients with DM	- Fruit juice: 120 mL/day for 0.5–1 month - Dried product: 13.7–30 g/day for 3 months - Polysaccharide extract: 300 mg/day (or 100 mg/kg/day) for 3 months	Triglycerides	MD = −17.7 mg/dL [95% CI: −40.7; 4.4]	PRISMA	2017	[10]
		Total cholesterol	MD = −11.6 mg/dL [95% CI: −29.0; 5.8]
		Fasting glucose	MD = −6.5 mg/dL [95% CI: −11.3; −1.8] (*)
		SBP	MD = 0.02 mmHg [95% CI: −4.26; 4.30]
		DBP	MD = −1.59 mmHg [95% CI: −4.57; 1.40]
		Body weight	MD = 0.13 kg [95% CI: −1.87; 2.14]
10 studies (n = 547)—healthy subjects or patients with DM, metabolic syndrome, or hypercholesterolemia	- Fruit juice: 120 mL/day for 0.5–1 month - Dried product: 7.3–90 g/day for 1.5–4 months - Polysaccharide extract: 0.72–150 mg/day for 1.5–3 months	Triglycerides	MD = −12.4 mg/dL [95% CI: −16.8; −8.0] (*)	PRISMA	2022	[9]
		HDL cholesterol	MD = 2.3 mg/dL [95% CI: 0.8; 3.5] (*)
		LDL cholesterol	MD = 0.00 mg/dL [95% CI: −14.3; 13.9]
		SBP	MD = 0.3 mmHg [95% CI: −1.5; 2.0]
		DPB	MD = − 0.6 mmHg [95% CI: −1.7; 0.5]
		Oxidative stress status (blood MDA)	g = −1.45 [95% CI: −2.75; −0.16] (*)
6 studies (n = 459)—healthy subjects or patients with DM	- Fruit juice: 120 mL/day for 1 month - Polysaccharide extract: 10–300 mg/day (or 100 mg/kg/day) for 1–3 months	Triglycerides	SMD = −0.46 [95% CI: −0.68; −0.23] (*)	-	2022	[11]
		Total cholesterol	SMD = −0.42 [95% CI: −0.95; 0.12]
		HDL cholesterol	SMD = 1.11 [95% CI: 0.51; 1.72] (*)
		LDL cholesterol	SMD = −0.53 [95% CI: −0.90; −0.16] (*)
		Fasting glucose	SMD = −0.71 [95% CI: −1.37; −0.04] (*)
5 studies (n = 259)—healthy subjects or patients with DM or metabolic syndrome	- Fruit juice: 120 mL/day for 1 month - Dried product: 14–15 g/day for 1.5–4 months - Polysaccharide extract: 300 mg/day for 1 month	Triglycerides	MD = −12.4 mg/dL, [95% CI: −17.7; −7.1] (*)	PRISMA	2023	[12]
		HDL cholesterol	MD = 2.7 mg/dL, [95% CI: 0.4; 5.0] (*)
		LDL cholesterol	MD = −8.1 mg/dL, [95% CI: −34.4; 17.8]
		Total cholesterol	MD = −4.3 mg/dL, [95% CI: −22.8; 14.3]

Table description: Studies are ordered by their year of publication. Legends: CI = Confidence Interval. DBP = Diastolic Blood Pressure. DM = Diabetes Mellitus. g = Hedges’ g. MD = Mean Difference. MDA = Malondialdehyde. SBP = Systolic Blood Pressure. SMD = Standardized Mean Difference. (*) = Significant result (p < 0.05) in favor of the consumption of Goji berries.

provides a summary of the available evidence.

The number of clinical trials included in each meta-analysis varied, ranging from a minimum of 4 to a maximum of 10, with participant numbers spanning from 161 to 548 (further details are available in Table 1). Participants in these trials were predominantly healthy individuals or those with metabolic disorders, such as diabetes mellitus, hypercholesterolemia, or metabolic syndrome. Goji berries were administered orally in various forms: as fruit juice at a daily dosage of 120 mL, as dried products at daily dosages ranging from 7 to 90 g, or as polysaccharide extracts primarily at daily dosages of 150–300 mg. The intervention duration varied, lasting from as short as 2 weeks to as long as 3 (or occasionally 4) months. The findings revealed that Goji berries and their derivatives were linked to decreased triglyceride levels, elevated HDL cholesterol levels (by approximately 10–15 mg/dL), reduced fasting glucose concentrations (by around 7–6 mg/dL), improved oxidative stress status, and enhanced quality of life, notably demonstrating an anti-fatigue effect. However, no significant effects were observed concerning changes in total cholesterol levels, body weight, or blood pressure. Three reviews were conducted in accordance with PRISMA guidelines, whereas such compliance was not explicitly stated in the remaining studies (further details are provided in Table 1).

4. Discussion

The findings of this literature overview align with other reviews, suggesting that Lycium barbarum polysaccharides hold promise for managing liver disease, dyslipidemia, and diabetes mellitus [13], and they exhibit prebiotic properties, fostering a beneficial gut microbiota environment [14]. The fruit extract additionally demonstrates neuroprotective properties, which are potentially beneficial in combating the effects of aging and vascular diseases, and preventing eye disorders [15,16,17,18]. Recent research has also hypothesized potential antitumor effects [19].

Goji berries are rich in polysaccharides, carotenoids, fiber, phenolic compounds, vitamins, and minerals, which have been demonstrated to exert pro-metabolic effects [20]. The presence of beta-sitosterol in the bark and berries aids in preventing cholesterol absorption in the gastrointestinal tract, potentially contributing to improved metabolic health [21]. Lycium polysaccharides exhibit hepatoprotective effects through modulation of NF-κB and MAPK pathways as well as autophagy, offering potential support for liver health [22]. Additionally, these compounds have been demonstrated to combat insulin resistance, ameliorate diabetic peripheral neuropathy, and protect against oxidative damage [23]. Recent studies have highlighted the ability of Lycium polysaccharides and micronutrients to modulate gut microbiota composition, leading to the production of active metabolites that contribute to overall host health [24]. Phenolic compounds, including rutin, isoquercitrin, and chlorogenic acid, are abundant in goji berries and have shown significant medicinal value: these phenolics provide antioxidant, anti-aging, hypoglycemic, and hypolipidemic effects, further enhancing the berries’ potential to support metabolic health and mitigate chronic disease risk [25]. These findings suggest that Lycium extracts not only possess direct physiological effects but also indirectly influence host health by regulating gut microbiota.

Goji berries, esteemed for their potential health benefits, are generally considered safe when consumed as a nutraceutical, with extensive research not identifying significant adverse effects at recommended doses. However, individuals with known allergies to fruits or berries should exercise caution, particularly those with lipid transfer protein food allergies who are considered at high risk for reactions [26]. Additionally, caution is advised for individuals on anticoagulant therapy as a few cases of elevated INR have been reported following consumption of concentrated Chinese herbal tea made from Lycium [27]. Moreover, Lycium extract has been found to induce CYP3A4 enzyme activity, potentially impacting the clearance of substrate drugs when used concurrently [28]. Therefore, consultation with a healthcare professional is advisable, especially for individuals with pre-existing medical conditions or those taking medications, to ensure compatibility and safety. Overall, when consumed in moderation as part of a balanced diet, goji berries can be a safe and nutritious addition to one’s health regimen.

5. Conclusions

Overall, the findings of this literature overview suggest that Goji berries and their derivatives may offer potential health benefits, including improvements in lipid profile, glucose metabolism, oxidative stress, and quality of life, although no significant effects were observed on body weight or blood pressure. Further studies on the topic are advised to elucidate the health effects of Goji berries, considering the observed variations in study design and methodology among the included meta-analyses, thus ensuring a comprehensive understanding of their potential health implications and guiding evidence-based recommendations for clinical practice.