juice results being less than expected (Kirkhus et al., 2012). This is could be due to various nutrients effecting absorption from the fruit. Unlike Dawczynski et al. (2013), Laidlaw et al. (2017) and Casanova et al. (2017) the total n-3 index was not tested, which has been shown to offer improvement towards risk factors of CVD. The larger sample size should show significant effects and as this doesn’t, future research should consider higher dosage through food intake such as in older studies like Marckmann et al. (1997).
A similar review from Bowen et al. (2016) shows trials published 2g/d) which provided smaller difference from the controls. Mozaffarian & Wu (2011), Burr et al., (1989) and the GISSI-Prevenzione Investigators (GISSI-Prevenzione, 1999) all show positive trend n-3 effects on cardiovascular risk in long term trials with statically significant group sizes. This would suggest a long follow up would increase results and validity. We see in Dawczynski et al. (2013) we see a notable difference with 0.8 and 3g/d in yoghurt. Although the p values and CI encourage a wide reliability, further research into this area would create better approaches in the n-3 guidelines given to people at risk of CVD.
In addition, a recent review from Balk et al. (2016) included 147 articles of RCT and prospective cohorts, found insufficient or low strength evidence between n-3FA in food or supplementation and major adverse CVD affects. It concedes with this review on high strength of evidence that n-3 oils increase levels of HDL-C and LDL-C (Balk et al., 2016). N-3 effects on CVD remain varied, Balk et al. (2016) advises that further trials may produce similar effective and ineffective results. This is important because it clarifies similar review problems of how the evidence in this study is so varied. Other reviews have assessed follow up period as showing the same results as 4 weeks-1 year in circulation of nutrients, with plasma levels changing in 6 weeks in Sanders & Hinds (1992). That the studies selected will produce similar results and external validity should still be relatively high from this (Mozaffarian et al., 2012; Thorngren et al., 1986).
Another way of improving future trials would be having a longer trial period with no n-3FA consumed, for longer than 3 months beforehand, Din et al. (2004), suggested a high intake of fish before a study can influence results, by unchanging levels significantly. The studies in this review state