All organs and systems of your body play an important role in promoting your overall health. One organ which is of particular importance to your life and health is your heart. There are numerous ways to measure if your heart is functioning optimally. You likely have heard of a term called heart rate which is the number of times your heart beats in a minute, pushing blood around your body. A normal, healthy heart rate at rest is 60-100 beats a minute. A term you may not have heard about is heart rate variability. This is the amount of time between one heartbeat to the next and may also play an important role in influencing your health and risk of disease.
Heart rate variability may influence your risk developing diseases such as heart disease, type two diabetes, and obesity. As well as influencing the rate of inflammation in your body and risk of psychiatric disorders.
Heart rate variability is not constant and can differ from one beat to the next. Your diet is one factor which may influence your heart rate variability both in the long and short term. There are associations with a higher heart rate variability, which is linked to positive health outcomes and better health status, when the Mediterranean diet is followed also when weight loss occurs. Also, in nutrients such as omega-3 fat, probiotics, prebiotics, B-vitamins, polyphenols. A diet which is high in trans or saturated fat and contains a large component of high glycaemic index carbohydrates seen in foods like refined grains and cereals is linked to reduce heart rate variability.
One study found that when salmon was eaten three times a week compared to meat three times a week sleep latency was reduced as well as daily functioning improved. The reason for this positive association is proposed to be duet to the omega-3 component in salmon.
Omega-3 is linked to greater parasympathetic nervous system activity. This is a type of nervous system which is used to help relax and rest your body and used during periods of digestion. Omega-3 fat is predicted to enhance your vagal tone. The vagal tone is the activity of your vagas nerve. Your vagas nerve is a part of your parasympathetic nervous system and directly influences the rate at which your heart beats. A higher vagal tone activated the parasympathetic nervous system and means that your heart rate can slow, and your body can move into a state of rest and digest functioning.
The Mediterranean diet is also linked to a higher heart rate variability. This is proposed to be due to the fish component of this style of eating. Omega-3 fat positively impact the rate of your heart in many ways both directly and indirectly. This includes affecting calcium regulatory proteins and ion channels. In the longer term, when the omega-3 fat is incorporated into the cell membranes this is seen to influence electrical activity within the cells themselves. Think of it like a ‘natural pacemaker’. This is proposed to be a factor reducing your heart rate and increasing your heart rate variability.
The indirect link of food on your mood is also proposed to impact your heart rate variability. Your diet choices impact your brain function, cognition as well as your mood, this then influences your heart rate variability. However, more research is still needed on how your brain effects your heart rate variability.
The overall message from these findings is that omega-3 fat may play a major role in promoting a higher heart rate variability. This is associated with a lower risk of certain diseases, inflammation, psychological well-being, and overall health. One good source of omega-3 fat is seafood. Two to three serves of seafood are recommended each week with a serve being 100 grams of cooked weight.
Take home message: All the systems in your body are affected by your diet. Your heart is no exception. There are numerous nutrients which are important for optimal functioning of your heart and omega-3 fat is one of these.
References:
- Young HA, Benton D. Heart-rate variability: a biomarker to study the influence of nutrition on physiological and psychological health? Behav Pharmacol. 2018 Apr;29(2 and 3-Spec Issue):140-151. doi: 10.1097/FBP.0000000000000383. PMID: 29543648; PMCID: PMC5882295.
- Jarczok MN, Kleber ME, Koenig J, Loerbroks A, Herr RM, Hoffmann K, et al. (2015). Investigating the associations of self-rated health: heart rate variability is more strongly associated than inflammatory and other frequently used biomarkers in a cross sectional occupational sample. PloS One 10:e0117196.
- Parasympathetic Nervous System (PSNS). Cleveland Clinic. https://my.clevelandclinic.org/health/body/23266-parasympathetic-nervous-system-psns
- How to Stimulate Your Vagus Nerve for Better Mental Health. Optimal Living Dynamics. https://sass.uottawa.ca/sites/sass.uottawa.ca/files/how_to_stimulate_your_vagus_nerve_for_better_mental_health_1.pdf
- Xin W, Wei W, Li XY. (2013). Short-term effects of fish-oil supplementation on heart rate variability in humans: a meta-analysis of randomized controlled trials. Am J Clin Nutr 97:926–935.
- Dai J, Lampert R, Wilson PW, Goldberg J, Ziegler TR, Vaccarino V. (2010). Mediterranean dietary pattern is associated with improved cardiac autonomic function among middle-aged men: a twin study. Circ Cardiovasc Qual Outcomes 3:366–373.
- Mozaffarian D, Stein PK, Prineas RJ, Siscovick DS. (2008). Dietary fish ω-3 fatty acid consumption and heart rate variability in US adults. Circulation 117:1130–1137.
- Soares-Miranda L, Stein PK, Imamura F, Sattelmair J, Lemaitre RN, Siscovick DS, et al. (2012). Trans-fatty acid consumption and heart rate variability in 2 separate cohorts of older and younger adults. Circ Arrhythm Electrophysiol 5:728–738.
- Benton D. (2010). Neuro-developmental and neuro-degeneration - are there critical times for nutritional intervention? Nutr Rev 68 (Suppll 1):S6–S10.
- Target Heart Rates Chart. American Heart Association. https://www.heart.org/en/healthy-living/fitness/fitness-basics/target-heart-rates
