Guava and Tomato Lower Risks for Neurodegenerative Diseases

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Did you know that guava and tomato are just two of the lycopene-rich fruits and vegetables that can protect your brain and reduce your risks for cancer, heart disease and bone fractures?

Lycopene, the pigment in red fruits and vegetables like pink guava and tomatoes, is an important dietary tool scientists are currently taunting in the prevention and suppression of neurodegenerative diseases. Past research has also shown lycopene to have antioxidant properties, which are effective in fighting other diseases such as cancer, precursors to heart diseases and bone conditions.

Neurodegenerative Disease

Lycopene demonstrated antioxidant properties in protecting the neural system in vitro and the consumption of lycopene-rich fruits and vegetables is recommended as a preventive strategy for neurodegenerative diseases.[i]

In addition to suppressing oxidative stress and inflammation in the brain, lycopene restores changes associated with neurodegenerative disorders, epileptic conditions, aging, brain hemorrhages, spinal cord injury and neuropathy and prevents proteinopathies, neuroinflammation, apoptosis, cerebral edema and synaptic dysfunction in the brain.[ii]

Lycopene also ameliorated neuroinflammation, oxidative stress, amyloid genesis and memory loss in an Alzheimer's-induced mice model, through mediating cell signaling pathways (MAPKs, NFκB and Nrf2) related to inflammation, and thus could be effective in preventing Alzheimer's disease.[iii]

In their in vitro study of mice, researchers found lycopene to be effective in reducing oxidative stress, which is considered a major cause of Alzheimer's disease, by reducing cell apoptosis through activation of the PI3K/Akt pathway.[iv]

Researchers studied 6,958 participants aged older than 50 years to assess the impact of carotenoids on mortality risk from Alzheimer's. High levels of lycopene, lutein and zeaxanthin were found to lower the risk of Alzheimer's mortality.[v] In an Alzheimer's-induced mice study, oxidative stress biomarkers were measured with two treatments --lycopene and lycopene combined with vitamin E.

The combination was synergistic in significantly decreasing memory impairments and improved three oxidative stress markers for Alzheimer's.[vi] In a rat study, researchers demonstrated that lycopene, a natural carotenoid, lowered aluminum-induced hippocampal lesions by inhibiting oxidative stress-mediated inflammation and apoptosis in the brain.[vii]

Similarly, lycopene was found to be very effective against age-induced cognitive impairment, memory loss and cognitive defects while reversing age-associated neuronal damage and synaptic dysfunction in brain synapses by mitigating oxidative stress and inflammation markers in a mouse model.[viii]

Cancer Risk

Twenty-six studies of 563,299 participants with 17,517 documented cases of prostate cancer were meta-analyzed, showing that higher lycopene intake (between 9 milligrams (mg) and 21 mg per day) reduced the incidence of prostate cancer.  The prostate cancer risk declined 18% with increasing consumption of lycopene (intake of tomatoes and watermelon) in a study of 404 participants.[ix]

In addition, researchers have found lycopene-rich foods like tomatoes to be positive for a variety of other cancers. In a meta-analysis including 15 studies of 644 animals, lycopene supplementation significantly reduced the incidence, number and growth of liver cancer.[x]

In their comprehensive review of the literature, scientists attested to tomato lycopene's preventive action against the formation and development of lung cancer as well.[xi] Lycopene supplementation in lung and liver tumor-induced mice reduced experimental tumor metastasis in vivo by decreasing tumor invasion, proliferation and angiogenesis.[xii]

In a pooled analysis of 21 studies, the group that consumed the most tomato products had the lowest risk for gastric cancer.[xiii] In a study of U.S. adults, tomato (86% lower risk) and lycopene (79% lower risk) intake was inversely related to all cancer deaths.[xiv]

Guava leaf extract has been shown to have a strong anticancer effect by preventing and stopping the growth of cancerous cells in in-vitro studies of animal induced cancers.[xv], [xvi]

Cardiovascular Disease Risk

In a meta-analysis of 14 studies, high dietary lycopene was significantly associated with low risk for cardiovascular disease, stroke and coronary heart disease.[xvii] Similarly, in an overview of 23,935 patients, mortality from coronary heart disease and cerebrovascular disease was significantly lower for those who had high tomato and lycopene intake, illustrating their cardioprotective abilities.[xviii]

A systematic review and meta-analysis of 21 studies showed that increasing the intake of tomatoes and lycopene products has positive effects on blood lipids, blood pressure and endothelial function, which make them valuable nutritional strategies to fight cardiovascular diseases.[1]

In a human study of 142 patients with cardiovascular disease, lycopene supplementation (7 mg per day) for four weeks increased serum lycopene levels more than four times, significantly improved tissue oxygenation and blood flow and reduced inflammatory oxidative damage markers threefold and oxidized lipid levels fivefold.[xix] Tomato juice (338 mg per day) treatment for 20 days also reduced inflammation (an underlying risk factor for cardiovascular disease and diabetes) in a controlled trial of 106 overweight and obese females.[xx]

Guava consumption was shown to have significant effects on heart health risk in 120 patients with high blood pressure Specifically, the study found a 9.9% net decrease in total cholesterol, 7.7% decrease in triglycerides and blood pressure lowered (systolic by 9 points and diastolic by 8 points) with an 8% net increase in high-density lipoprotein cholesterol after 12 weeks of guava fruit treatment.[xxi]

Bone Health

In another study, 370 men and 576 women (70 to 80 years of age) from the Framingham Osteoporosis Study completed a food frequency questionnaire in 1988 to 1989 and were followed  for 17 years for bone fractures.

Results showed that subjects with higher lycopene intake had significantly lower risk of hip and nonvertebral fractures.[xxii] Tomato and tomato products, as rich sources of lycopene, have been shown to decrease bone loss, which significantly lowers risk for fractures in vivo and in vitro studies of postmenopausal women.[xxiii]

In vitro and clinical studies of osteoblast cells found the intake of a lycopene-rich tomato sauce (5 mg and 10 mg) in 39 postmenopausal women resulted in no significant bone density loss with the treatment and better bone turnover results compared to those in the non-tomato sauce control group, showing that tomato sauce can be used to lower risk of bone loss and to prevent osteoporosis.[xxiv]

Top 12 Lycopene Food Sources

So which fruits and veggies are reliable lycopene sources? Boost your lycopene levels by increasing your consumption of the top foods found in Table 1.[xxv] Although there is no daily minimum requirement for lycopene, sources suggest consuming from 8 mg to 21 mg per day for optimal health.[xxvi]

Table 1. Top Fruits and Vegetables Highest in Lycopene (By Milligrams Per Cup)

1. Tomato Puree (50)[xxvii]

2.  Sun Dried Tomatoes (25)[xxviii]

3. Guavas (8.6)

4.  Fresh Tomato (7.3)

5. Watermelon (6.9)

6.  Pink Grapefruit (3.3)

7.  Papaya (2.7)

8.  Red Bell Peppers (0.5)

9.  Persimmon (0.3)

10. Asparagus (0.05)

11. Red Cabbage (0.02)

12. Mangos (0.01)

Sensitivities to Nightshade Vegetables

Some people may experience chronic pain and inflammation from a sensitivity to foods called “nightshade” vegetables. That is because they can contain glycoalkaloids such as solanine in potato and eggplant,[xxix] tomatine in tomato and capsaicin in garden peppers as well as wheat lectin or chitin-binding lectins found in tomatoes[xxx] and red pepper.

Reactions should be monitored for their effect on the digestive system and arthritic symptoms, and triggering foods should be avoided completely if the sensitivity continues or slowly brought back into the diet one by one if tolerated.[xxxi] Pesticide-treated and genetically modified (GMO) foods are the most problematic and buying non-GMO and organic nightshade vegetables is essential.

Lycopene gives fruits and vegetables, like tomatoes, guavas, watermelon and red bell peppers, their reddish hues and packs a punch for its neuroprotective, anticancer, bone protective and heart healthy properties. To read more about the impact of guavas and tomatoes on your health, see's research database on lycopene.


[1] Ho Ming Cheng, Georgios Koutsidis, John K Lodge, Ammar Ashor, Mario Siervo, José Lara. Tomato and lycopene supplementation and cardiovascular risk factors: A systematic review and meta-analysis. Atherosclerosis. 2017 Jan 13 ;257:100-108. Epub 2017 Jan 13. PMID: 28129549

[i] Shanshan Ou, Yinchao Fang, Hai Tang, Tong Wu, Lizhi Chen, Mei Jiang, Lingqi Zhou, Jie Xu, Kaihua Guo. Lycopene protects neuroblastoma cells against oxidative damage via depression of ER stress. J Food Sci. 2020 Oct ;85(10):3552-3561. Epub 2020 Sep 4. PMID: 32885410

[ii] Rajib Paul, Muhammed Khairujjaman Mazumder, Joyobrato Nath, Satarupa Deb, Satinath Paul, Pallab Bhattacharya, Anupom Borah. Lycopene - A pleiotropic neuroprotective nutraceutical: Deciphering its therapeutic potentials in broad spectrum neurological disorders. Neurochem Int. 2020 Nov ;140:104823. Epub 2020 Aug 20. PMID: 32827559

[iii] Jia Wang, Lixia Li, Zhuo Wang, Yifan Cui, Xintong Tan, Tian Yuan, Qian Liu, Zhigang Liu, Xuebo Liu. Supplementation of lycopene attenuates lipopolysaccharide-induced amyloidogenesis and cognitive impairments via mediating neuroinflammation and oxidative stress. J Nutr Biochem. 2018 Feb 2 ;56:16-25. Epub 2018 Feb 2. PMID: 29454265

[iv] Cuiqin Huang, Caiyan Wen, Mei Yang, Danhui Gan, Chongzhu Fan, An Li, Qin Li, Jiayi Zhao, Lihong Zhu, Daxiang Lu. Lycopene protects against t-BHP-induced neuronal oxidative damage and apoptosis via activation of the PI3K/Akt pathway. Mol Biol Rep. 2019 Jun ;46(3):3387-3397. Epub 2019 Apr 20. PMID: 31006097

[v] Jin-young Min, Kyoung-bok Min. Serum lycopene, lutein and zeaxanthin, and the risk of Alzheimer's disease mortality in older adults. Dement Geriatr Cogn Disord. 2014 ;37(3-4):246-56. Epub 2013 Nov 15. PMID: 24247062

[vi] Lixia Yu, Weiguang Wang, Wei Pang, Zhonghai Xiao, Yugang Jiang, Yan Hong. Dietary Lycopene Supplementation Improves Cognitive Performances in Tau Transgenic Mice Expressing P301L Mutation via Inhibiting Oxidative Stress and Tau Hyperphosphorylation. J Alzheimers Dis. 2017 ;57(2):475-482. PMID: 28269786

[vii] Zheng Cao, Peiyan Wang, Xiang Gao, Bing Shao, Shuchen Zhao, Yanfei Li. Lycopene attenuates aluminum-induced hippocampal lesions by inhibiting oxidative stress-mediated inflammation and apoptosis in the rat. J Inorg Biochem. 2019 Apr ;193:143-151. Epub 2019 Feb 1. PMID: 30743053

[viii] Beita Zhao, Hua Liu, Jiamin Wang, Pujie Liu, Xintong Tan, Bo Ren, Zhigang Liu, Xuebo Liu. Lycopene Supplementation Attenuates Oxidative Stress, Neuroinflammation, and Cognitive Impairment in Aged CD-1 Mice. J Agric Food Chem. 2018 Mar 6. Epub 2018 Mar 6. PMID: 29509007

[ix] Le Jian, Chuan-Jun Du, Andy H Lee, Colin W Binns. Do dietary lycopene and other carotenoids protect against prostate cancer? Int J Cancer. 2005 Mar 1;113(6):1010-4. PMID: 15514967

[x] Abraham Nigussie Mekuria, Abera Kenay Tura, Bisrat Hagos, Mekonnen Sisay, Jemal Abdela, Kirubel Minsamo Mishore, Birhanu Motbaynor. Anti-Cancer Effects of Lycopene in Animal Models of Hepatocellular Carcinoma: A Systematic Review and Meta-Analysis. Front Pharmacol. 2020 ;11:1306. Epub 2020 Aug 21. PMID: 32982734

[xi]  Paola Palozza, Rossella E Simone, Assunta Catalano, Maria Cristina Mele. Tomato lycopene and lung cancer prevention: from experimental to human studies. Cancers (Basel). 2011 ;3(2):2333-57. Epub 2011 May 11. PMID: 24212813

[xii] Chin-Shiu Huang, Jiunn-Wang Liao, Miao-Lin Hu. Lycopene inhibits experimental metastasis of human hepatoma SK-Hep-1 cells in athymic nude mice. J Nutr. 2008 Mar ;138(3):538-43. PMID: 18287363

[xiii] Tingsong Yang, Xiaohu Yang, Xudong Wang, Yiling Wang, Zhenshun Song. The role of tomato products and lycopene in the prevention of gastric cancer: a meta-analysis of epidemiologic studies. Med Hypotheses. 2013 Apr ;80(4):383-8. Epub 2013 Jan 24. PMID: 23352874

[xiv] Mohsen Mazidi, Gordon A Ferns, Maciej Banach. A high consumption of tomato and lycopene is associated with a lower risk of cancer mortality: results from a multi-ethnic cohort. Public Health Nutr. 2020 Feb 27:1-7. Epub 2020 Feb 27. PMID: 32102720

[xv] Chen KC, Hsieh CL, Peng CC, Hsieh-Li HM, Chiang HS, Huang KD, Peng RY. Brain derived metastatic prostate cancer DU-145 cells are effectively inhibited in vitro by guava (Psidium gujava L.) leaf extracts. Nutr Cancer. 2007;58(1):93-106. doi: 10.1080/01635580701308240. PMID: 17571972.

[xvi] Manosroi J, Dhumtanom P, Manosroi A. Anti-proliferative activity of essential oil extracted from Thai medicinal plants on KB and P388 cell lines. Cancer Lett. 2006 Apr 8;235(1):114-20. doi: 10.1016/j.canlet.2005.04.021. Epub 2005 Jun 23. PMID: 15979235.

[xvii] Bo Song, Kai Liu, Yuan Gao, Lu Zhao, Hui Fang, Yusheng Li, Lulu Pei, Yuming Xu. Lycopene and risk of cardiovascular diseases: A meta-analysis of observational studies. Mol Nutr Food Res. 2017 Mar 20. Epub 2017 Mar 20. PMID: 28318092

[xx] Mahsa Ghavipour, Ahmad Saedisomeolia, Mahmoud Djalali, Giti Sotoudeh, Mohammad Reza Eshraghyan, Ali Malekshahi Moghadam, Lisa G Wood. Tomato juice consumption reduces systemic inflammation in overweight and obese females. Br J Nutr. 2013 Jun ;109(11):2031-5. Epub 2012 Oct 15. PMID: 23069270

[xxi] Singh, R. B., Rastogi, S.S., Singh, R. Ghosh, S., Niaz, M.A. Effects of guava intake on serum total and high-density lipoprotein cholesterol levels and on systemic blood pressure. American Journal of Cardiology, Volume 70, Issue 15, 1287 - 1291 DOI: 10.1016/0002-9149(92)90763-O, PMID: 1332463

[xxii] Shivani Sahni, Marian T Hannan, Jeffrey Blumberg, L Adrienne Cupples, Douglas P Kiel, Katherine L Tucker Protective effect of total carotenoid and lycopene intake on the risk of hip fracture: a 17-year follow-up from the Framingham Osteoporosis Study. J Bone Miner Res. 2009 Jun;24(6):1086-94. PMID: 19138129

[xxiii] Umani S Walallawita, Frances M Wolber, Ayelet Ziv-Gal, Marlena C Kruger, Julian A Heyes. Potential Role of Lycopene in the Prevention of Postmenopausal Bone Loss: Evidence from Molecular to Clinical Studies. Int J Mol Sci. 2020 Sep 27 ;21(19). Epub 2020 Sep 27. PMID: 32992481

[xxiv] Cristina Russo, Yvelise Ferro, Samantha Maurotti, Maria Antonietta Salvati, Elisa Mazza, Roberta Pujia, Rosa Terracciano, Giuseppina Maggisano, Rosario Mare, Sandro Giannini, Stefano Romeo, Arturo Pujia, Tiziana Montalcini. Lycopene and bone: an in vitro investigation and a pilot prospective clinical study. J Transl Med. 2020 Jan 29 ;18(1):43. Epub 2020 Jan 29. PMID: 31996227

[xxv] My Food Data. Articles. High Lycopene Foods.

[xxvi] Healthline. Nutrition. Lycopene.

[xxviii] Healthy Eating. Health Benefits Eating Sun Dried Tomatoes.

[xxix] Patel B, Schutte R, Sporns P, Doyle J, Jewel L, Fedorak RN. Potato glycoalkaloids adversely affect intestinal permeability and aggravate inflammatory bowel disease. Inflamm Bowel Dis. 2002 Sep;8(5):340-6. doi: 10.1097/00054725-200209000-00005. PMID: 12479649.

[xxx] Willy J Peumans, Pierre Rougé, Els J M Van Damme. The tomato lectin consists of two homologous chitin-binding modules separated by an extensin-like linker. Biochem J. 2003 Dec 15;376(Pt 3):717-24. PMID: 14503921

[xxxi] GreenMedInfo. Link Between Nightshades Chronic Pain and Inflammation.

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