Health Claims and Doses of Fish Oil Supplements in the US

Long-chain PUFA and painful temporomandibular disorder in the Hispanic Community Health Study/Study of Latinos

OBJECTIVE

n-6 and n-3 long-chain PUFA play opposing roles in inflammation, anxiety and nociception, all of which are closely associated with chronic pain. We hypothesised that diets high in n-6 arachidonic acid (C20:4n-6, AA) and low in combined n-3 EPA (C20:5n-3, EPA) and DHA (C22:6n-3, DHA) would be associated with higher odds of painful temporomandibular disorder (TMD).

DESIGN

We analysed baseline data from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). Two 24-h dietary recall surveys quantified intake of long-chain n-6 and n-3 PUFA along with their precursors, linoleic acid (C18:2n-6, LA) and alpha linolenic acid (C18:3n-3, ALA), respectively. n-3 PUFA supplementation was quantified. Interviewer-administered questions assessed TMD. Survey multiple logistic regression estimated covariate-adjusted OR and 95 % confidence limits (CL) for associations between PUFA and TMD.

SETTING

From 2008 to 2011, HCHS/SOL recruited 16 415 adults of Hispanic/Latino backgrounds (Cuban, Puerto Rican, Dominican, Mexican, Central/South American), through field centres located in Miami, FL; San Diego CA; Chicago, IL; and the Bronx, NY.

PARTICIPANTS

13 870 participants with non-missing data.

RESULTS

In analysis adjusted for covariates, each sd increase in dietary intake of C20:4n-6, AA was associated with 12 % higher odds of TMD (OR = 1·12, CL: 1·01, 1·24). Although the dietary intake of combined long-chain C20:5n-3, EPA and C22:6n-3 DHA was not associated with TMD, each sd increase in n-3 dietary supplement was associated with lower odds of TMD.

CONCLUSIONS

A diet rich in C20:4n-6, AA was associated with higher odds of painful TMD.

Oral Lipids/Fatty Acids Supplements and Eczema: What Is Known?

The pathogenesis of atopic dermatitis (AD) points to skin barrier dysfunction as a critical piece of the puzzle. Deficiencies in fatty acids and ceramides-key elements of the skin barrier-have been linked to AD. Fatty acids can be separated into omega-3 and omega-6, which can be found in a variety of foods such as fish, nuts, seeds, and even plants. In dogs, supplementation with oral fatty acids has shown promising benefits. This review aims to explore whether humans can similarly benefit from these supplements based on current literature. The results of our search varied by compound type. For borage oil and evening primrose oil, evidence of their effectiveness is mixed, though they may offer some preventative benefits. Fish oil supplements appear to be effective in treating AD, as they reduce clinical scores and symptom severity. Oral ceramides, blackcurrant seed oil, and hempseed oil have yet to be thoroughly studied, but preliminary results are promising. Among the studies, the supplementation doses and duration of treatment varied extensively. The literature did not provide comparative analysis between the supplements, and data on the overall safety and tolerability of these supplements are limited. While some evidence is promising, the reliability of these products, as well as their optimal dosage and frequency, remains uncertain.

Bioavailability of EPA and DHA in humans - A comprehensive review

The bioavailability of long-chain omega-3 fatty acids is a critical yet often overlooked factor influencing their efficacy. This review evaluates the bioavailability of EPA/DHA from acute (single-dose) and chronic human studies, focusing on (a) chemical forms such as triacylglycerols (TAG, natural and re-esterified, rTAG), non-esterified fatty acids (NEFA), and phospholipids (PL) from sources like fish, krill, and microalgae, and (b) delivery methods like microencapsulation and emulsification. Bioavailability for isolated chemically forms followed the order: NEFA > PL > rTAG > unmodified TAG > ethyl esters (EE). However, varying oil compositions complicate conclusions about source-specific bioavailability. Significant differences observed in acute bioavailability studies (e.g., faster absorption) often did not translate into long-term impacts in chronic supplementation studies. This raises questions about the clinical relevance of acute findings, especially given that n-3 PUFA supplements are typically consumed long-term. Methodological limitations, such as inappropriate biomarkers, short sampling windows, and inadequate product characterization, hinder the reliability and comparability of studies. The review emphasizes the need for standardized protocols and robust chronic studies to clarify the clinical implications of bioavailability differences. Future research should prioritize biomarkers that reflect sustained n-3 PUFA status to better understand the health benefits of various EPA and DHA formulations.

Regulatory Compliance of Health Claims on Omega-3 Fatty Acid Food Supplements

Unlike the mandatory information that must be provided on a food supplement label, health claims are voluntary. This study assesses the regulatory compliance of omega-3 fatty acid (ω-3-FA) supplement label claims. Of the 97 supplements, 76 (78.4%) carried verbal claims referring to active substance, of which 68 (89.5%) were claims specific to ω-3-FA. According to the European Union Health Claims Registry, 107 claims listed on 59 supplements were authorized, as opposed to nine unauthorized claims on nine supplements. The degree to which claims aligned with regulatory standards, expressed in terms of scores scaled from 0 to 1, was the highest for supplements intended for pregnant women (1), while, in the case of adults, the mean score was 0.76 ± 0.35, and, in case of children, was 0.85 ± 0.27. Statistical analysis revealed a minor tendency for higher health claim scores to be associated with lower product prices. Furthermore, differences in compliance levels across groups of supplements formed according to the country of origin/sources of ω-3-FA/target populations were explored. The main differences were associated with products from Sweden and Italy/fish oil/supplements for pregnant women. A comparison of the daily intake of ω-3-FA provided by the supplement (based on labeled information) with the intake requirements for supplements with claims referring to ω-3-FA, supported 91 claims, five were unsubstantiated, and 11 were missing required data. Supplements also contained mineral- (19 approved) and vitamin-related claims (73, of which 9 were unauthorized). This study's findings reveal the extent of misuse of labelled information in markets that require pre-market supplement registration. Importantly, the non-compliance of health claims can significantly undermine consumer trust.

Longitudinal study of seafood and fish oil supplement intake and risk of persistent tinnitus

BACKGROUND

Persistent tinnitus is common, disabling, and difficult to treat. Diet has been implicated in tinnitus etiology, but studies are inconsistent, and longitudinal data are scarce. Seafood intake is associated with a lower risk of hearing loss, but the longitudinal association with tinnitus is unknown.

OBJECTIVES

We examined the independent associations of seafood intake, fish oil supplement use, and risk of developing persistent tinnitus.

METHODS

This prospective cohort study followed 73,482 females in the Nurses' Health Study II from 1991 to 2021. Diet was assessed using a validated food frequency questionnaire every 4 y. Multivariable-adjusted Cox proportional hazards regression was used to evaluate independent associations between total seafood intake, specific types of fish, shellfish, fish oil supplements, and risk of persistent tinnitus (defined as tinnitus experienced daily).

RESULTS

After 1,998,421 person-y of follow-up, 9362 cases of incident persistent tinnitus were reported. Seafood intake was independently associated with a lower risk of developing persistent tinnitus. Compared with participants who never or rarely consumed seafood, the multivariable-adjusted hazard ratios (MVHRs; 95% confidence interval) for tinnitus were 0.87 (0.78, 0.95) among participants who consumed 1 serving/wk, 0.77 (0.68, 0.86) for 2-4 servings/wk, and 0.79 (0.64, 0.96) for 5+/servings/wk (P-trend < 0.0001). Examined individually, higher intakes of tuna fish, light-meat fish and shellfish were associated with lower risk. Compared with participants who never or rarely consumed the specific type, the MVHRs for consumption of 1+ servings/wk were 0.84 (0.78, 0.90) (P-trend < 0.0001) for tuna fish, 0.91 (0.83, 0.99) (P-trend = 0.04) for light-meat fish, and 0.82 (0.72, 0.93) (P-trend < 0.0001) for shellfish. A higher risk for dark-meat fish intake was suggested [MVHR: 1.09 (0.99, 1.21) (P-trend = 0.04)]. Fish oil supplement use (yes/no) was associated with higher risk [MVHR: 1.12 (1.06, 1.19)].

CONCLUSIONS

Regular consumption of tuna fish, light-meat fish, or shellfish is associated with a lower risk of developing persistent tinnitus in females. Fish oil supplement use is associated with higher risk.

Omega-3 Fatty Acids and Arrhythmias

The pro- and antiarrhythmic effects of omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been extensively studied in preclinical and human trials. Despite early evidence of an antiarrhythmic role of n-3 PUFA in the prevention of sudden cardiac death and postoperative and persistent atrial fibrillation (AF), subsequent well-designed randomized trials have largely not shown an antiarrhythmic benefit. Two trials that tested moderate and high-dose n-3 PUFA demonstrated a reduction in sudden cardiac death, but these findings have not been widely replicated, and the potential of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) to reduce arrhythmic death in combination, or as monotherapy, remains uncertain. The accumulated clinical evidence does not support supplementation of n-3 PUFA for postoperative AF or secondary prevention of AF. Several large, contemporary, randomized controlled trials of high-dose n-3 PUFA for primary or secondary cardiovascular prevention have demonstrated a small, significant, dose-dependent increased risk of incident AF compared with mineral oil or corn oil comparator. These findings were reproduced with both icosapent ethyl monotherapy and a mixed EPA+DHA formulation. The proarrhythmic mechanism of increased AF in contemporary cohorts exposed to high-dose n-3 PUFA is unknown. EPA and DHA and their metabolites have pleiotropic cardiometabolic and pro- and antiarrhythmic effects, including modification of the lipid raft microenvironment; alteration of cell membrane structure and fluidity; modulation of sodium, potassium, and calcium currents; and regulation of gene transcription, cell proliferation, and inflammation. Further characterization of the complex association between EPA, EPA+DHA, and DHA and AF is needed. Which formulations, dose ranges, and patient subgroups are at highest risk, remain unclear.

Docosahexaenoic Acid Coordinating with Sodium Selenite Promotes Paraptosis in Colorectal Cancer Cells by Disrupting the Redox Homeostasis and Activating the MAPK Pathway

Tumor cells are characterized by a delicate balance between elevated oxidative stress and enhanced antioxidant capacity. This intricate equilibrium, maintained within a threshold known as redox homeostasis, offers a unique perspective for cancer treatment by modulating reactive oxygen species (ROS) levels beyond cellular tolerability, thereby disrupting this balance. However, currently used chemotherapy drugs require larger doses to increase ROS levels beyond the redox homeostasis threshold, which may cause serious side effects. How to disrupt redox homeostasis in cancer cells more effectively remains a challenge. In this study, we found that sodium selenite and docosahexaenoic acid (DHA), a polyunsaturated fatty acid extracted from marine fish, synergistically induced cytotoxic effects in colorectal cancer (CRC) cells. Physiological doses of DHA simultaneously upregulated oxidation and antioxidant levels within the threshold range without affecting cell viability. However, it rendered the cells more susceptible to reaching the upper limit of the threshold of redox homeostasis, facilitating the elevation of ROS levels beyond the threshold by combining with low doses of sodium selenite, thereby disrupting redox homeostasis and inducing MAPK-mediated paraptosis. This study highlights the synergistic anticancer effects of sodium selenite and DHA, which induce paraptosis by disrupting redox homeostasis in tumor cells. These findings offer a novel strategy for more targeted and less toxic cancer therapies for colorectal cancer treatment.

Use of Dietary Supplements Among People With Atherosclerotic Cardiovascular Disease in the United States: A Population-Based Analysis From NHANES

BACKGROUND

Dietary supplement use is prevalent in the general US population, but little is known regarding the driving reasons for their use among those with atherosclerotic cardiovascular disease (ASCVD).

METHODS AND RESULTS

Data from the National Health and Nutrition Examination Survey (NHANES) from 2017 to March 2020 were used to identify adults with ASCVD. Supplement use was assessed by interviewers using label review, and surveys captured self-reported reasons for use. Demographic, clinical, medication, and laboratory characteristics were compared between supplement users and nonusers. Among individuals with ASCVD in the National Health and Nutrition Examination Survey (n=965; mean age, 65 years; 56.1% men; 73.7% White individuals), 73.1% reported taking ≥1 dietary supplements, most commonly multivitamins (35.4%), vitamin D (30.8%), and fish oil (19.8%). Of those taking supplements, 47.3% report taking them under the advisement of a health professional. Nearly one fifth (17.9%) reported taking at least 1 supplement for "heart health," most commonly fish oil (11.1%), followed by CoQ10 (4.2%) and resveratrol (1.5%). Supplement users were older (68 versus 62 years; P=0.003), included more women (45.8% versus 37.7%; P=0.17), were less likely to smoke (11.0% versus 36.4%; P<0.001), had higher levels of education (P=0.005) and income (P<0.001), and higher use of statins (69.4% versus 55.8%; P=0.046).

CONCLUSIONS

Supplement use is common in people with ASCVD. Among the top 3 supplements, a substantial minority were being taken under the direction of health professionals. Supplement users often report taking supplements "for heart health," despite a lack of randomized trial evidence for benefit in ASCVD, indicating a need for more patient and clinician education regarding health benefits of dietary supplements in ASCVD.