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Tomatoes and Diabetes

December 15, 2010 Written by JP    [Font too small?]

Are you diabetic? I’m not. But I approach my health care as if I were and I think most people should as well. By this, I don’t mean that the majority of you should start popping medications that help manage blood sugar. Far from it. Why do that when you can most likely attain healthy glucose control via exercise, stress management and a whole food diet? That’s the game plan I advocate for most of my clients. However there’s more to supporting diabetic health than simply sustaining optimal blood sugar levels. One of the other pieces of the puzzle involves restoring oxidative balance within the body. Eating or supplementing with foods rich in antioxidants may very well reduce the risk of health threats that are commonly associated with adult-onset diabetes and beyond.

Tomatoes are an abundant source of antioxidant pigments known as carotenoids. In fact, the characteristic red hue is largely brought about by one member of this phytochemical family known as lycopene. Several studies spanning the past few decades are providing clues that eating various tomato-based foods may afford significant cardiovascular support in men and women with type 2 diabetes. This is the most common variety of the disease and is also the most responsive to natural interventions. (1,2,3)

The current edition of the Journal of the Neurological Sciences reports that diabetics with hypertension are 48% more likely to suffer from age-related cognitive changes than those who are normotensive. Fortunately, another publication appearing in the December 2010 issue of the International Journal of Food Sciences and Nutrition reveals that achieving healthy blood pressure may be as simple as eating more tomatoes. The latter paper notes that tomatoes contain nutrients that extend beyond just the antioxidant lycopene. They’re also a good source of beta-carotene (pro-vitamin A), folate, potassium and Vitamins C, E and K. Perhaps that’s why a recent 8 week intervention providing a daily dose of 200 grams of raw tomato resulted in “significant decreases in systolic and diastolic blood pressure” in a group of 32 type 2 diabetics. (4,5)

A summary article in the journal Current Pharmaceutical Biotechnology explains that cardiovascular dysfunction is a leading cause of mortality in type 2 diabetics. An “imbalance between the production of reactive oxygen and nitrogen species (ROS and RNS)” is widely believed to be a contributing factor in the development and progression of this troublesome trend. The consumption of cooked tomatoes is one way to tip the oxidative balance back in your favor. Researchers from the People’s College of Medical Sciences and Research Center in Bhanpur, India have found that long term tomato intake in diabetics results in higher levels of protective antioxidant enzymes and a lower concentration of lipid peroxidation. (6,7)

Daily Tomato Juice Consumption Reduces Platelet Clumping in Diabetics
Source: JAMA. 2004;292(7):805-806. (link)

Another important risk factor in diabetes mellitus is an increased risk of abnormal blood clotting and subsequent atherothrombotic events. A deleterious process referred to as platelet hyperreactivity “plays a pivotal role” in said circulatory abnormalities. Regularly drinking tomato juice may provide a natural and safe means of addressing this health threat. The basis for this statement is a pilot study published in the Journal of the American Medical Association. In it, middle-aged men and women with type 2 diabetes were given 250 ml of tomato juice or a placebo over a 3 week period. The participants in the tomato juice group demonstrated a statistically relevant decline in platelet aggregation by the end of the short trial. No changes in blood sugar control were found in the two study groups. (8,9)

Incorporating tomatoes in your dietary regimen is by no means a panacea for diabetes or any other health condition. Rather, the key to their value has a lot to do with what they offer from a nutritional standpoint. Chief among their attributes is that most tomatoes are relatively low in carbohydrates and rich in fiber and nutrients. They also offer some much needed color to the average diet. Most naturally occurring pigments in whole foods yield protective effects in the human body. Think of the deep greens in spinach, the intense orange of pumpkins or the rich purple spectrum found in wine. The health promoting properties of these foods are partially due to the phytochemicals that form the colors that make them so distinctive. Eating a low glycemic, “rainbow” style diet is one of the most reliable ways of reducing your risk of diabetes and related comorbidities. That’s the advice I give and it’s also the advice I follow myself. (10,11,12)

Note: Please check out the “Comments & Updates” section of this blog – at the bottom of the page. You can find the latest research about this topic there!

Be well!


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Posted in Diabetes, Food and Drink, Nutrition

13 Comments & Updates to “Tomatoes and Diabetes”

  1. Sai Says:

    Good Day JP!

    Good info about tomatoes (especially more than the lycopene we know about) and the research results! So cooking is it better to have cooked tomatoes or raw (like juicing tomato)? Looks like both would be good and that is good news..Thanks again for a very good posting. Happy Holidays..

    Best Regards


  2. JP Says:

    Greetings, Sai!

    It seems as though both cooked and raw tomatoes are advantageous. The first study cited used them in a raw form with good effect. The second and third employed cooked and heat-treated tomatoes (juice) with positive results. My only suggestion would be to consume any form of tomatoes with a good source of fatty acids such as extra virgin olive oil. The combination of carotenoids + lipids assists the absorption of these valuable antioxidants.

    Be well and happy holidays to you and yours!


  3. Pradip Gharpure Says:

    Very useful and interesting article. By the way I like tomatoes very much, so it will be easy for me to increase its intake.

  4. anne h Says:

    JP –
    I must confess –
    I never liked tomatoes before.
    But now I do -very much!
    Maybe grilled.

  5. JP Says:

    Thank you Anne and Pradip!

    Lightly grilled would be great. A little extra virgin olive oil, a sprinkle of Italian herbs and pepper … delicious! 🙂

    Be well!


  6. JP Says:

    Update: Related tomato juice benefits …


    Food Chem Toxicol. 2014 Sep 3.

    Dietary supplementation with tomato-juice in patients with metabolic syndrome: A suggestion to alleviate detrimental clinical factors.

    Lycopene, a carotenoid, is known for its antioxidant properties. Little is known, though, about the relationship of dietary tomato-juice intake and risks factors, like inflammation, insulin resistance and hyperlipidemia, implicated in metabolic syndrome. In the present study, we examined whether supplementation with tomato-juice has any implication on the risk status of patients with metabolic syndrome. A comparative study was conducted in 27 individuals diagnosed with metabolic syndrome. Fifteen of them were instructed to use commercially available tomato-juice as refreshment 4 times a week over a period of two months and twelve individuals served as the control group. Several parameters reflective of the metabolic syndrome were monitored both in the group supplemented with tomato juice and in the control group (ADMA for entdothelial function, TNF-α and IL-6 for inflammation, FIRI for insulin resistance). There was a significant improvement in the inflammation status and the endothelial dysfunction of the tomato-juice supplemented patients. At the same time, insulin resistance improved and a pronounced decrease in LDL was recorded, along with a slight increase in HDL. The results of the present study suggest an alleviating effect of tomato-juice with regard to risk factors associated with metabolic syndrome.

    Be well!


  7. JP Says:

    Update 04/20/15:


    Nutrition Journal (2015) 14:34

    Tomato juice intake increases resting energy expenditure and improves hypertriglyceridemia in middle-aged women

    Background: Tomato-based food products have health-promoting and disease-preventing effects. Some tomato juice ingredients may have health benefits for middle-aged women, including women with menopausal symptoms and cardiovascular diseases. We investigated the net effect of tomato juice intake on several health parameters in women in this age group.

    Methods: An open-label, single-arm study was conducted, involving 95 women (40-60-years-old) who had at least one menopausal symptom. The participants refrained from foods and drinks rich in tomato and tomato-based products for 2 weeks prior to the study and during the 8 weeks of tomato juice consumption. After the run-in period, the women were asked to consume 200 mL of unsalted tomato juice, twice daily for 8 weeks. Their menopausal symptoms were evaluated using the Menopausal Symptom Scale (MSS), Hospital Anxiety and Depression Scale (HADS), and Athens Insomnia Scale (AIS) before the study, and at 4 and 8 weeks after study commencement. At the same times, body composition; blood pressure; heart rate; resting energy expenditures (REEs); and serum levels of triglyceride (TG), cholesterol, glucose, and hemoglobin A1c were measured.

    Results: Ninety-three women (98%) completed the study. The following parameters showed significant changes, compared with baseline, at study weeks 4 and 8 (mean ± standard deviation at baseline, week 4, and week 8): (1) the MSS score improved (32.8 ± 17.0, 28.1 ± 16.3, 27.6 ± 16.3; P < 0.0001, repeated measures analysis of variance(ANOVA)), (2) the HADS-anxiety subscale score improved (5.3 ± 2.7, 4.8 ± 2.4, 4.9 ± 2.9; P = 0.041, Friedman test), (3) heart rate increased (62.6 ± 9.4 bpm, 64.4 ± 8.6 bpm, 63.8 ± 8.2 bpm; P = 0.028, Friedman test), (4) REE increased (1980 ± 368 kcal/day, 2108 ± 440 kcal/day, 2149 ± 470 kcal/day; P = 0.0030, repeated measures ANOVA), (5) serum TG level decreased in the subgroup of women (n = 22) who had high TG (150 mg/dL or higher) at baseline (237.8 ± 88.9 mg/dL, 166.7 ± 86.1 mg/dL, 170.9 ± 109.7 mg/dL; P = 0.0002, Friedman test).

    Conclusions: Tomato juice intake alleviated menopausal symptoms, including anxiety, increased REEs and heart rate, and lowered high baseline serum TG levels in middle-aged women.

    Be well!


  8. JP Says:

    Update 07/10/15:


    Am J Clin Nutr. 2015 Jul 8.

    Olive oil consumption and risk of type 2 diabetes in US women.

    BACKGROUND: Olive oil has been shown to improve various cardiometabolic risk factors. However, to our knowledge, the association between olive oil intake and type 2 diabetes (T2D) has never been evaluated in the US population.

    OBJECTIVE: We aimed to examine the association between olive oil intake and incident T2D.

    DESIGN: We followed 59,930 women aged 37-65 y from the Nurses’ Health Study (NHS) and 85,157 women aged 26-45 y from the NHS II who were free of diabetes, cardiovascular disease, and cancer at baseline. Diet was assessed by validated food-frequency questionnaires, and data were updated every 4 y. Incident cases of T2D were identified through self-report and confirmed by supplementary questionnaires.

    RESULTS: After 22 y of follow-up, we documented 5738 and 3914 incident cases of T2D in the NHS and NHS II, respectively. With the use of Cox regression models with repeated measurements of diet and multivariate adjustment for major lifestyle and dietary factors, the pooled HR (95% CI) of T2D in those who consumed >1 tablespoon (>8 g) of total olive oil per day compared with those who never consumed olive oil was 0.90 (0.82, 0.99). The corresponding HRs (95% CIs) were 0.95 (0.87, 1.04) for salad dressing olive oil and 0.85 (0.74, 0.98) for olive oil added to food or bread. We estimated that substituting olive oil (8 g/d) for stick margarine, butter, or mayonnaise was associated with 5%, 8%, and 15% lower risk of T2D, respectively, in the pooled analysis of both cohorts.

    CONCLUSIONS: Our results suggest that higher olive oil intake is associated with modestly lower risk of T2D in women and that hypothetically substituting other types of fats and salad dressings (stick margarine, butter, and mayonnaise) with olive oil is inversely associated with T2D.

    Be well!


  9. JP Says:

    Updated 08/03/15:


    J Int Soc Prev Community Dent. 2015 May;5(Suppl 1):S25-31.

    Systemic lycopene as an adjunct to scaling and root planing in chronic periodontitis patients with type 2 diabetes mellitus.

    BACKGROUND: Patients with type 2 diabetes have an increased prevalence of periodontitis and, in turn, periodontitis adversely affects the diabetic status. Oxidative stress plays a key role in affecting the pathophysiology of both the diseases and adjunctive systemic antioxidant therapy may have beneficial effect on the treatment outcome. This study was planned to compare the efficacy of systemic antioxidant therapy with lycopene as an adjunct to scaling and root planing versus scaling and root planing alone in chronic periodontitis patients with type 2 diabetes mellitus.

    MATERIALS AND METHODS: 40 diabetic subjects with periodontitis, attending the OP wing of the Department of Periodontics of a tertiary referral care hospital were randomized and equally divided into group A and group B. Diabetes status was recorded as per ADA guidelines and the periodontitis status as per American Academy of Periodontology (AAP) guidelines. Group A patients underwent scaling and root planing with administration of lycopene 8 mg and group B patients were treated with scaling and root planing alone. Clinical parameters like gingival index (GI), probing depth (PD), and clinical attachment level (CAL) were recorded. Serum markers, i.e. malondialdehyde (MDA) (TBARS assay) and C reactive protein (CRP) (ELISA), and glycated hemoglobin (HbA1c) levels were assessed at baseline and at 2 months and 6 months post-therapy.

    RESULTS: Inter-group comparison showed group A giving statistically significant results in reducing mean serum MDA levels at 2 months and 6 months, and in reducing mean PD (mm) and mean HbA1c (%) levels at 2 months (P < 0.005). CONCLUSION: Lycopene as an adjunctive treatment was effective in reducing oxidative stress and restoring altered glycemic levels. Further longitudinal studies with a larger sample size are required to establish the role of lycopene in the management of chronic periodontitis. Be well! JP

  10. JP Says:

    Updated 08/03/15:


    Cardiovasc Diabetol. 2014 Jan 14;13:16.

    A randomised controlled trial of increasing fruit and vegetable intake and how this influences the carotenoid concentration and activities of PON-1 and LCAT in HDL from subjects with type 2 diabetes.

    BACKGROUND: High density lipoproteins (HDL) have many cardioprotective roles; however, in subjects with type 2 diabetes (T2D) these cardioprotective properties are diminished. Conversely, increased fruit and vegetable (F&V) intake may reduce cardiovascular disease risk, although direct trial evidence of a mechanism by which this occurs in subjects with T2D is lacking. Therefore, the aim of this study was to examine if increased F&V consumption influenced the carotenoid content and enzymes associated with the antioxidant properties of HDL in subjects with T2D.

    METHODS: Eighty obese subjects with T2D were randomised to a 1- or ≥6-portion/day F&V diet for 8-weeks. Fasting serum was collected pre- and post-intervention. HDL was subfractionated into HDL2 and HDL3 by rapid ultracentrifugation. Carotenoids were measured in serum, HDL2 and HDL3 by high performance liquid chromatography. The activity of paraoxonase-1 (PON-1) was measured in serum, HDL2 and HDL3 by a spectrophotometric assay, while the activity of lecithin cholesterol acyltransferase (LCAT) was measured in serum, HDL2 and HDL3 by a fluorometric assay.

    RESULTS: In the ≥6- vs. 1-portion post-intervention comparisons, carotenoids increased in serum, HDL2 and particularly HDL3, (α-carotene, p = 0.008; β-cryptoxanthin, p = 0.042; lutein, p = 0.012; lycopene, p = 0.016), as did the activities of PON-1 and LCAT in HDL3 (p = 0.006 and 0.044, respectively).

    CONCLUSION: To our knowledge, this is the first study in subjects with T2D to demonstrate that increased F&V intake augmented the carotenoid content and influenced enzymes associated with the antioxidant properties of HDL. We suggest that these changes would enhance the cardioprotective properties of this lipoprotein.

    Be well!


  11. JP Says:

    Updated 08/03/15:


    Diabetes Metab Syndr Obes. 2013 Jul 26;6:263-73.

    Effect of tomato consumption on high-density lipoprotein cholesterol level: a randomized, single-blinded, controlled clinical trial.

    INTRODUCTION: Epidemiologic evidence suggests that tomato-based products could reduce the risk of cardiovascular diseases. One of the main cardiovascular risk factors is low levels of high-density lipoprotein cholesterol (HDL-C). This study aimed to prospectively evaluate the effect of tomato consumption on HDL-C levels.

    SUBJECT AND METHODS: We conducted a randomized, single-blinded, controlled clinical trial. We screened 432 subjects with a complete lipid profile. Those individuals with low HDL-C (men <40 mg/dL and women <50 mg/dL) but normal triglyceride levels (<150 mg/dL) were included. Selected participants completed a 2-week run-in period on an isocaloric diet and then were randomized to receive 300 g of cucumber (control group) or two uncooked Roma tomatoes a day for 4 weeks.

    RESULTS: A total of 50 individuals (women = 41; 82%) with a mean age of 42 ± 15.5 years and a mean body mass index of 27.6 ± 5.0 kg/m(2) completed the study. A significant increase in HDL-C levels was observed in the tomato group (from 36.5 ± 7.5 mg/dL to 41.6 ± 6.9 mg/dL, P < 0.0001 versus the control group). After stratification by gender, the difference in HDL-C levels was only significant in women. The mean HDL-C increase was 5.0 ± 2.8 mg/dL (range 1-12 mg/dL). Twenty patients (40%) finished the study with levels >40 mg/dL. A linear regression model that adjusted for those parameters that impact HDL-C levels (age, gender, waist-to-hip ratio, body mass index, fasting triglyceride concentration, simple sugars, alcohol, physical activity, and omega-3 consumption) showed an independent association between tomato consumption and the increase in HDL-C (r (2) = 0.69; P < 0.0001). CONCLUSION: Raw tomato consumption produced a favorable effect on HDL-C levels in overweight women. Be well! JP

  12. JP Says:

    Updated 12/21/16:


    BMC Cardiovasc Disord. 2016 Oct 28;16(1):203.

    Association between markers of glycemia and carotid intima-media thickness: the MARK study.

    BACKGROUND: Carotid intima-media thickness (C-IMT) is a reliable predictor of cardiovascular events. We Investigated the relationship between markers of glycemia and C-IMT in intermediate-risk cardiovascular patients.

    METHODS: This study analyzed 427 subjects, aged 35 to 74 years (mean, 60.3 ± 8.5 years), 55 % women, enrolled into the MARK study. Including 231 subjects defined as normal glucose, 104 subjects classified as prediabetes and 92 with type 2 diabetes mellitus. Carotid ultrasound was used to measure C-IMT and the presence of plaques. Fasting plasma glucose (mg/dl) and glycated hemoglobin (%) (HbA1c) were measured using standard enzymatic automated methods. Postprandial glucose (mg/dl) was self-measured by patients at home 2 h after meals (breakfast, lunch and dinner) for 1 day.

    RESULTS: The C-IMT shows a positive correlation with fasting plasma glucose, postprandial glucose and HbA1c. Multiple linear regression analysis showed a positive association between HbA1c and C-IMT, with a 0.016 mm and 0.019 mm increase in mean and maximum C-IMT per 1 % increase in HbA1c. In addition, an association between fasting plasma glucose and C-IMT was found with an increase of 0.004 and 0.005 mm in mean and maximum C-IMT per 10 mg/dl in fasting plasma glucose. We also observed a graded association between fasting plasma glucose, postprandial glucose and HbA1c and the presence of carotid target organ damage (TOD), with an odds ratio of 1.013, 1.010 and 1.425, respectively.

    CONCLUSION: The results of this study suggest that the fasting plasma glucose and HbA1c, but not postprandial glucose, are associated with C-IMT media and maximum. The patients who present with a metabolic glucose alteration have more risk of developing carotid TOD.

    Be well!


  13. JP Says:

    Updated 06/20/17:


    Br J Nutr. 2017 Jun 19:1-8.

    May the Mediterranean diet attenuate the risk of type 2 diabetes associated with obesity: the Seguimiento Universidad de Navarra (SUN) cohort.

    It is likely that the Mediterranean diet (MedDiet) may mitigate the adverse effects of obesity on the incidence of type 2 diabetes mellitus (T2DM). We assessed this hypothesis in a cohort of 18 225 participants initially free of diabetes (mean age: 38 years, 61 % women). A validated semi-quantitative 136-item FFQ was used to assess dietary intake and to build a 0-9 score of adherence to MedDiet. After a median of 9·5-year follow-up, 136 incident cases of T2DM were confirmed during 173 591 person-years follow-up. When MedDiet adherence was low (≤4 points), the multivariable-adjusted hazard ratios (HR) were 4·07 (95 % CI 1·58, 10·50) for participants with BMI 25-29·99 kg/m2 and 17·70 (95 % CI 6·29, 49·78) kg/m2 for participants with BMI≥30 kg/m2, (v.4 points), these multivariable-adjusted HR were 3·13 (95 % CI 1·63, 6·01) and 10·70 (95 % CI 4·98, 22·99) for BMI 25-30 and ≥30 kg/m2, respectively. The P value for the interaction was statistically significant (P=0·002). When we assessed both variables (BMI and MedDiet) as continuous, the P value for their interaction product-term was marginally significant (P=0·051) in fully adjusted models. This effect modification was not explained by weight changes during follow-up. Our results suggest that the MedDiet may attenuate the adverse effects of obesity on the risk of T2DM.

    Be well!


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