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Fish Oil and Kidney Health

January 3, 2011 Written by JP    [Font too small?]

Whenever I begin working with new clients, I always ask them to fill out a few forms and questionnaires. Some people do so without any issue. But every once in a while I’m asked why it’s necessary to provide answers to medical questions that appear to be unrelated to the health concerns at hand. Without fail, I explain that dietary choices, environment, lifestyle factors and psychological matters quite often contribute to physical complaints. This is a foundational principle of holistic medicine and one that cannot be under emphasized.

An example of this philosophy can be applied to the topic of kidney stones. Renal lithiasis or kidney stones are formed when there is an imbalance in certain acids and minerals found in urine. This can cause crystals and “stones” to form and sometimes become lodged in the urinary tract. This, in turn, affects the ability of urine to pass through and thereby often results in severe pain in the back, groin region and lower abdomen. However, these and other dreaded symptoms associated with kidney stones are only a small part of the picture. As it turns out, the incidence of renal lithiasis may also be related to other more significant health concerns.

I’ll get back to the more global impact of kidney stones later in this column. But first I’d like to provide some practical information about a relatively unknown way to reduce the likelihood of developing such deposits in the first place. A just published study in the Journal of Urology reports that 900 mg of EPA (eicosapentaenoic acid) and 600 mg of DHA (docosahexaenoic acid) daily for 30 days resulted in a 23% reduction in calcium oxalate “due to significantly decreased urinary oxalate excretion” in a group of 15 healthy adults. This indicates that these fish oil-based omega-3 fatty acids may benefit “calcium oxalate stone formers” when used as a long-term preventive measure. (1)

This isn’t the first mention of a proposed link between select fatty acids and kidney stones. Previous trials conducted in animal and human subjects reveal that: a) a dosage of 1,800 mg of EPA/day lowers the recurrence of kidney stones in patients who already received treatment; b) a combination of EPA and lipoic acid (an anti-oxideant) inhibits stone formation and limits oxalate toxicity to the kidneys in an experimental animal model; c) a study from 1996 found that 30 days of fish oil supplementation “lowered calcium and oxalate urine excretion, and normalized erythrocyte oxalate exchange”; d) populations that consume large quantities of fish, such as Greenland Eskimos, are documented as having a lower risk of “degenerative diseases including stone disease”. (2,3,4,5)

Kidney Stones Are Associated with a Higher Risk of Chronic Kidney Disease

Source: CJASN April 2009 vol. 4 no. 4 804-811 (link)

I want to revert back to the holistic model I mentioned earlier. Recent publications in prestigious medical journals are now pointing to a probable link between components of kidney stones including uric acid and vascular conditions, such as heart disease and stroke. High levels of uric acid are also connected to an increased risk of gout and kidney disease. A dramatic illustration appears in the October 2010 issue of the Journal of the American Society of Nephrology. In it, an examination of 10,860 healthy men and women, and 4,564 “stone formers” found that those at risk for kidney stones were 38% more likely to have a heart attack and at a 31% greater risk of developing chronic kidney disease or other co-morbidities over a 9 year follow-up period. (6,7,8)

I think it’s no coincidence that eating fish regularly and/or supplementing with fish oil also appears to protect against the very same conditions previously mentioned. Numerous studies in the medical literature show a robust benefit of omega-3 fatty acids in patients with chronic renal failure. The same is true in relation to DHA and EPA plasma levels and the risk of heart attacks or myocardial infarctions. More studies in this area are clearly needed. However, based on what we know now, it seems that fish oil supports both cardiovascular and renal health in part by moderating blood pressure, heart rate and triglycerides in at-risk patients. So even if you’re unaware of any genetic predisposition toward kidney stones, you might still want to consider whether you’re getting enough omega-3s in your daily diet. (9,10,11,12,13)

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 Alternative Therapies, Nutrition, Nutritional Supplements

18 Comments & Updates to “Fish Oil and Kidney Health”

  1. anne h Says:

    I know I don’t get enough.
    So now I know better!

  2. Paul Jaminet Says:

    Hi JP,

    Moderate omega-3 consumption is surely helpful, but there are some risks to very high omega-3 intake. Epidemiologically high omega-3 intake among older women is associated with higher rates of kidney stones. I discuss why that may be in this post, which is mainly about why very low-carb diets increase kidney stone formation: http://perfecthealthdiet.com/?p=1177.

    Best, Paul

  3. JP Says:

    A good resolution for 2011, Anne! 🙂

    Go to it!

    Be well!


  4. JP Says:

    Interesting information, Paul. Thank you for sharing it.

    Be well!


  5. Iggy Dalrymple Says:

    Have had 2 kidney stone removals in past 12 months, the last one surgically through my back from my right kidney. I’m a long time heavy user of fish oil. I now take 4 grams of Sam’s Club “Triple Strength” fish oil plus 2 grams of krill oil. Am the 3rd generation of stone formers in my family.

    Refused the “Shock-Wave Lithotripsy” for fear of damage to my pancreas.

  6. Iggy Dalrymple Says:

    Better link: http://www.jurology.com/article/S0022-5347(05)00989-4/abstract

  7. JP Says:

    Thanks for sharing that, Iggy. I know you’ve tried many strategies to prevent kidney stones.

    Here’s hoping they won’t return.

    Be well!


  8. Cynthia D'Auria Says:

    Hello JP,
    I found the article regarding Papaya interesting! I started taking Advanced enzyme system which contains this substance.
    A few months ago, and recently I have been having pain in my Great Toe, I do not eat foods that would cause “gout”.
    I thought about what was new in my diet and came up with AES…
    Could this be a causative agent?
    I am sure you know what it contains.
    Your input will be appreciated.

  9. JP Says:

    Hi, Cynthia.

    The article I wrote about (fermented, ripe) papaya (https://www.healthyfellow.com/1093/fermented-papaya-preparation/) didn’t specifically focus on green papaya and papain – two minor ingredients in Advanced Enzyme System. Having said that, any change in your diet or lifestyle that appears to coincide with unwelcome effects should be investigated.

    In most instances, enzyme blends do not cause inflammation or pain of any kind. Sometimes, they even help to decrease inflammatory markers and reduce discomfort. But, there are always exceptions to the rule – allergic reactions, interactions, sensitivities and other unforeseen variables. So, if your use of this supplement is the only thing you can think of that may be causative, then I think it’s reasonable to avoid it for a period of time to see how you react. And, if you feel as though you truly require digestive enzyme support, you can always switch over to a formula with fewer ingredients and papaya-free during the trial period. I hope this helps!

    Be well!


  10. JP Says:

    Update: The role that calcium and hydration play in kidney stone formation …


    J Am Coll Nutr. 2015 Apr 9:1-7.

    Effects of Hydration and Calcium Supplementation on Urine Calcium Concentration in Healthy Postmenopausal Women.

    OBJECTIVE: The aim of this study was to determine whether calcium supplementation, compared with placebo, increases urine calcium concentrations to levels indicative of increased renal stone risk, and the role that fluid intake, as indicated by urine volume, may play in mitigating this risk.

    METHODS: This is a secondary analysis of data from a randomized placebo-controlled trial of 500 mg/d calcium supplementation to prevent bone loss. Subjects were 240 white postmenopausal women age 40 to 70 years in good general health. Effects of supplementation on 1-year changes in 24h urine calcium concentration and urine volume were examined.

    RESULTS: Both treatment group and urine volume were strong independent predictors of urine calcium concentration (p < 0.001). Among subjects with urine volume under 2 L/24 h, more than half of placebo subjects were at lowest risk for renal stones compared with less than 35% of calcium-supplemented subjects. Among those with higher urine volumes, all placebo subjects and more than 80% of calcium supplemented subjects were at lowest risk. CONCLUSIONS: The increased risk of renal stones with calcium supplement use may be largely eliminated with adequate fluid intake, but older adults may not spontaneously consume adequate fluids to minimize this risk and should be counseled to do so. Be well! JP

  11. JP Says:

    Update 04/17/15:


    Exp Clin Endocrinol Diabetes 14 April 2015

    Curcumin Attenuates Urinary Excretion of Albumin in Type II Diabetic Patients with Enhancing Nuclear Factor Erythroid-Derived 2-Like 2 (Nrf2) System and Repressing Inflammatory Signaling Efficacies

    Curcumin has a therapeutic potential in treating diabetic kidney disease (DKD) while potential mechanisms underlining this beneficial effect remain to be elucidated. In the present study, curcumin intervention was performed in patients with Type II diabetes mellitus (T2DM) by oral intake of curcumin at the dose of 500 mg/day for a period of 15–30 days. Nephritic excretion of urinary micro-albumin (U-mAlb) and blood metabolic indexes were assessed before and after this intervention. In addition, the lipid oxidation index, malondialdehyde (MDA) in plasma and the status of anti-oxidative Nrf2 system in blood lymphocytes were measured. The effect of curcumin on inflammation was assessed by measuring plasma lipopolysaccharide (LPS) content and inflammatory signaling protein in blood lymphocytes. A self-comparison method was used for assessing statistical significances of these measurements. Here we show that curcumin intervention markedly attenuated U-mAlb excretion without affecting metabolic control of participated patients. In addition, curcumin reduced plasma MDA level with enhanced the Nrf2 system specifically regulated protein, NAD(P)H quinone oxidoreductase 1 (NQO-1) together with other anti-oxidative enzymes in patients’ blood lymphocytes. Furthermore, we observed reduced plasma LPS content and increased IκB, an inhibitory protein on inflammatory signaling in patient’s lymphocytes after curcumin administration. Finally, several gut bacterials important for maintaining gut barrier integrity and function were upregulated by curcumin.

    In conclusion, short-term curcumin intervention ablates DKD progress with activating Nrf2 anti-oxidative system and anti-inflammatory efficacies in patients with T2DM.

    Be well!


  12. JP Says:

    Updated 12/05/15:


    Medicine (Baltimore). 2015 Nov;94(47):e2181.

    Long-Term Effects of a Very Low Carbohydrate Compared With a High Carbohydrate Diet on Renal Function in Individuals With Type 2 Diabetes: A Randomized Trial.

    To compare the long-term effects of a very low carbohydrate, high-protein, low saturated fat (LC) diet with a traditional high unrefined carbohydrate, low-fat (HC) diet on markers of renal function in obese adults with type 2 diabetes (T2DM), but without overt kidney disease.One hundred fifteen adults (BMI 34.6 ± 4.3 kg/m, age 58 ± 7 years, HbA1c 7.3 ± 1.1%, 56 ± 12 mmol/mol, serum creatinine (SCr) 69 ± 15 μmol/L, glomerular filtration rate estimated by the Chronic Kidney Disease Epidemiology Collaboration formula (eGFR 94 ± 12 mL/min/1.73 m)) were randomized to consume either an LC (14% energy as carbohydrate [CHO < 50 g/day], 28% protein [PRO], 58% fat [<10% saturated fat]) or an HC (53% CHO, 17% PRO, 30% fat [<10% saturated fat]) energy-matched, weight-loss diet combined with supervised exercise training (60 min, 3 day/wk) for 12 months. Body weight, blood pressure, and renal function assessed by eGFR, estimated creatinine clearance (Cockcroft-Gault, Salazar-Corcoran) and albumin excretion rate (AER), were measured pre- and post-intervention.Both groups achieved similar completion rates (LC 71%, HC 65%) and reductions in weight (mean [95% CI]; -9.3 [-10.6, -8.0] kg) and blood pressure (-6 [-9, -4]/-6[-8, -5] mmHg), P ≥ 0.18. Protein intake calculated from 24 hours urinary urea was higher in the LC than HC group (LC 120.1 ± 38.2 g/day, 1.3 g/kg/day; HC 95.8 ± 27.8 g/day, 1 g/kg/day), P < 0.001 diet effect. Changes in SCr (LC 3 [1, 5], HC 1 [-1, 3] μmol/L) and eGFR (LC -4 [-6, -2], HC -2 [-3, 0] mL/min/1.73 m) did not differ between diets (P = 0.25). AER decreased independent of diet composition (LC --2.4 [-6, 1.2], HC -1.8 [-5.4, 1.8] mg/24 h, P = 0.24); 6 participants (LC 3, HC 3) had moderately elevated AER at baseline (30-300 mg/24 h), which normalized in 4 participants (LC 2, HC 2) after 52 weeks.Compared with a traditional HC weight loss diet, consumption of an LC high protein diet does not adversely affect clinical markers of renal function in obese adults with T2DM and no preexisting kidney disease. Be well! JP

  13. JP Says:

    Updated 2/4/16:


    Nutr J. 2016 Jan 27;15(1):10.

    Association between probiotic and yogurt consumption and kidney disease: insights from NHANES.

    BACKGROUND: Data from experimental animals suggest that probiotic supplements may retard CKD progression. However, the relationship between probiotic use, frequent yogurt consumption (as a natural probiotic source), and kidney parameters have not been evaluated in humans.

    FINDINGS: We utilized NHANES data, and analyzed the association of probiotic alone (1999-2012) and yogurt/probiotic (2003-2006) use with albuminuria and eGFR after adjustment for demographic and clinical parameters. Frequent yogurt consumption was defined as thrice or more weekly over the year prior to the interview. Frequent yogurt/probiotic consumers had lower adjusted odds of developing combined outcome (albuminuria and/or eGFR < 60 ml/min/1.73 m(2)) compared to infrequent consumers (OR = 0.76; 95 % CI = 0.61-0.94). When evaluated separately, frequent consumers had lower odds of albuminuria and nonsignificant trend towards decreased odds of low eGFR compared to infrequent consumers. In the probiotic cohort, probiotic consumers were found to have a lower adjusted odds of albuminuria compared to nonusers (OR = 0.59; 95 % CI = 0.37-0.94). CONCLUSION: Frequent yogurt and/or probiotics use is associated with decreased odds of proteinuric kidney disease. These hypothesis-generating results warrant further translational studies to further delineate the relationship between yogurt/probiotics with kidney dysfunction, as well as microbiome and dysbiosis as potential mediators. Be well! JP

  14. JP Says:

    Updated 02/01/17:


    Complement Ther Med. 2017 Feb;30:79-83.

    Effects of a 12-week program of Tai Chi exercise on the kidney disease quality of life and physical functioning of patients with end-stage renal disease on hemodialysis.

    BACKGROUND: Previous studies have shown that exercise training in patients with end-stage renal disease could improve their physical functioning and quality of life. Nevertheless, few studies have evaluated the effects of Tai Chi exercise in patients on hemodialysis.

    OBJECTIVE: To investigate the effects of a Tai Chi exercise intervention on the quality of life and physical functioning in end-stage renal disease patients on hemodialysis.

    DESIGN: A pre-post experimental design.

    SETTING: Patients, aged 20 years or older, on hemodialysis recruited from the hemodialysis unit at a medical center in central Taiwan were assigned, based on their own preference, to either a control group (n=25) or an intervention group (n=21).

    INTERVENTION: A weekly one-hour short-form Yang style Tai Chi session for a total of 12 weeks.

    MAIN OUTCOME MEASURES: Physical functioning and Kidney Disease Quality of Life (KDQOL) at the baseline and at the end of the intervention.

    RESULTS: The least square means of repetition of sit-to-stand cycles in one minute (STS-60), 6-min walk test, and gait speed test were significantly improved in the intervention group. In addition, the least square means of the five different dimensions of the KDQOL were all significantly higher in the intervention group, except the SF-12 physical health score.

    CONCLUSIONS: Improvements in the kidney disease quality of life and physical functioning were observed in Taiwanese patients on hemodialysis with a 12-week Tai Chi exercise intervention.

    Be well!


  15. JP Says:

    Updated 06/20/17:


    Asia Pac J Clin Nutr. 2017;26(4):598-605.

    Dietary fiber intake is associated with chronic kidney disease (CKD) progression and cardiovascular risk, but not protein nutritional status, in adults with CKD.

    BACKGROUND AND OBJECTIVES: Evidence suggests that dietary fiber benefits patients with chronic kidney disease (CKD); however, this conclusion requires further validation. In this study, we examined the effects of dietary fiber on kidney function, inflammation, indoxyl sulfate, nutritional status, and cardiovascular risk in patients with advanced CKD.

    METHODS AND STUDY DESIGN: We performed linear regressions to assess the association between dietary fiber intake and CKD parameters. The aforementioned parameters were compared over an 18-month follow- up period. Kaplan-Meier analysis was used to investigate the association between fiber intake and Cardiac vascular disease (CVD).

    RESULTS: In total, 157 patients were included in this study. Dietary fiber and inflammatory indices were associated (interleukin [IL]-6: β=-0.024, p=0.035). The differential estimated glomerular filtration rate (ΔeGFR) as well as levels of C-reactive protein, IL-6, indoxyl sulfate, and serum cholesterol in the higher fiber intake (>=25 g/day) group were lower than those in the lower fiber intake (<25 g/day) group (p<0.05). Differences in IL-6 and indoxyl sulfate levels were more significant in patients in the higher protein intake group (p<0.05). Dietary fiber intake may be a protective factor associated with CVD (hazard ratio=0.537 and 0.305- 0.947). The protein nutritional status was not different between the two groups (p>0.05).

    CONCLUSIONS: Our results suggest that increasing fiber intake can retard the decrease in the eGFR; can reduce the levels of proinflammatory factors, indoxyl sulfate, and serum cholesterol; and is negatively associated with cardiovascular risk, but does not disrupt the nutritional status of patients with CKD.

    Be well!


  16. JP Says:

    Updated 07/02/17:


    J Am Soc Nephrol. 2017 Jun 30.

    A Randomized Trial of Vitamin D Supplementation on Vascular Function in CKD.

    Vitamin D deficiency associates with mortality in patients with CKD, and vitamin D supplementation might mitigate cardiovascular disease risk in CKD. In this randomized, double-blind, placebo-controlled trial, we investigated the effect of cholecalciferol supplementation on vascular function in 120 patients of either sex, aged 18-70 years, with nondiabetic CKD stage 3-4 and vitamin D deficiency (serum 25-hydroxyvitamin D ≤20 ng/ml). We randomized patients using a 1:1 ratio to receive either two directly observed oral doses of cholecalciferol (300,000 IU) or matching placebo at baseline and 8 weeks. The primary outcome was change in endothelium-dependent brachial artery flow-mediated dilation at 16 weeks. Secondary outcome measures included changes in pulse wave velocity and circulating biomarkers. Cholecalciferol supplementation significantly increased endothelium-dependent brachial artery flow-mediated dilation at 16 weeks, whereas placebo did not (between-group difference in mean change: 5.49%; 95% confidence interval, 4.34% to 6.64%; P<0.001). Intervention also led to significant favorable changes in pulse wave velocity and circulating IL-6 levels. Thus, in nondiabetic patients with stage 3-4 CKD and vitamin D deficiency, vitamin D supplementation may improve vascular function.

    Be well!


  17. JP Says:

    Updated 06/17/18:


    Diabetes Metab Res Rev. 2018 Jun 14:e3032.


    Meta-analysis was conducted to clarify the effect of low carbohydrate diet (LCD) on renal function in patients with type 2 diabetes mellitus (T2DM). An extensive literature search was conducted on scientific databases including PubMed, Scopus, and Cochrane Library until September 2017. Only controlled trials on human subjects written in English were included in this meta-analysis. Several markers of renal function were compared between subjects who adopted a LCD or control diet, including estimated glomerular filtration rate (eGFR), creatinine clearance, urinary albumin, serum creatinine, and serum uric acid. Random effect model was used in the analysis of each marker. In this meta-analysis, 12 controlled trials were selected, which involved 942 participants (500 received LCD and 442 received a control diet). The pooled standardized mean difference (SMD) of eGFR from LCD vs. control diet was not different (Pooled SMD: 0.26; 95% CI:-0.03, 0.55; p=0.08). Investigation on creatinine clearance also showed no significant difference (Pooled SMD: 0.53; 95% CI: -0.38, 1.44; p=0.26). Other comparisons from urinary albumin (Pooled SMD: -0.04; 95% CI: 0.75, 0.67; p=0.90), serum creatinine (Pooled SMD: -0.57; 95% CI: -1.51, 0.38; p=0.24), and serum uric acid (Pooled SMD: -8.86; 95% CI: -4.00, 2.28; p=0.59) also showed insignificant difference in the results. In the present meta-analysis, no effect on markers of renal function was found after provision of a low carbohydrate diet compared with a control diet in patients with T2DM.

    Be well!


  18. JP Says:

    Updated 06/26/18:


    Nephrol Dial Transplant. 2018 Jun 22.

    Effect of prebiotic (fructooligosaccharide) on uremic toxins of chronic kidney disease patients: a randomized controlled trial.

    Background: Microbial-derived uremic toxins, p-cresyl sulfate (PCS), indoxyl sulfate (IS) and indole 3-acetic acid (IAA), have been associated with the burden of chronic kidney disease (CKD). Prebiotics have emerged as an alternative to modulate the gut environment and to attenuate toxin production. This trial aims to investigate the effect of a prebiotic fructooligosaccharide (FOS) on uremic toxins of non-dialysis-dependent CKD (NDD-CKD) patients.

    Methods: A double-blind, placebo-controlled, randomized trial was conducted for 3 months. In all, 50 nondiabetic NDD-CKD patients [estimated glomerular filtration rate (eGFR) <45 mL/min/1.73 m2], aged 18-80 years, were allocated to prebiotic (FOS, 12 g/day) or placebo (maltodextrin, 12 g/day) groups. Primary outcomes were changes in serum (total and free) and urinary (total) PCS. Secondary outcomes included changes in IS, IAA, serum markers of intestinal permeability (zonulin), gut-trophic factors (epidermal growth factor and glucagon-like peptide-2), eGFR, inflammation (high sensitive c-reactive protein and interleukin-6), homeostatic model assessment-insulin resistance, lipid profile and gastrointestinal symptoms.

    Results: From 50 participants (54% men, 57.3 ± 14.6 years and eGFR 21.4 ± 7.6 mL/min/1.73 m2), 46 completed the follow-up. No changes in dietary intake or gastrointestinal symptoms were observed. There was a trend in the difference of serum total ΔPCS (treatment effect adjusted for baseline levels: -12.4 mg/L; 95% confidence interval (-5.6 to 0.9 mg/L; P = 0.07) and serum-free Δ%PCS [intervention -8.6 (-41.5 to 13.9%) versus placebo 3.5 (-28.8 to 85.5%); P = 0.07] between the groups. The trend in the difference of serum total ΔPCS was independent of eGFR and dietary protein:fiber ratio intake. No difference was found in urinary PCS. Aside from the decreased high-density lipoprotein cholesterol in the intervention, no differences were observed in the change of IS, IAA or other secondary outcome between the groups.

    Conclusions: Our result suggests the potential of FOS in reducing serum total and free PCS in nondiabetic NDD-CKD patients.

    Be well!


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