In the nick of time: Can timing phytonutrient intake help reduce oxidative stress after a meal?
Previous studies have shown oxidative stress increases following a high carbohydrate and high fat meal. Our latest review investigates how timing the intake of phytonutrients may help reduce this effect.
Over the last 100 years, our eating habits have evolved from a diet high in whole foods, wholegrains and less refined food, to a modern diet containing high amounts of refined, processed carbohydrates and high saturated fat foods. But, what does this mean for our health?
Previous studies have shown that modern Western-style diets, which are typically high in refined carbohydrates and saturated fats, increase a biochemical process in our body called oxidative stress [1]. Oxidative stress is an imbalance of excess reactive oxygen species and inadequate antioxidants in the body, which can lead to cell and tissue damage. Excessive oxidative stress leads to chronic inflammation in the body and may lead to the development of chronic diseases such as cardiovascular disease and cancer.
Phytonutrients are natural compounds found in plant foods such as vegetables, fruit, whole grain products and legumes. Studies have shown these phytonutrients may suppress oxidative stress after a meal, however results are mixed [2]. This may be because phytonutrients are only present in the body for a short time after we eat them, so when they are consumed may impact how effective they are at reducing oxidative stress caused by a meal. Indeed, the same phytonutrient consumed in a solid versus liquid form (e.g. from a whole fruit versus a juice) can be present in the body for a different period of time [3]. Therefore understanding when these phytonutrients are at their maximum level in the body after eating (also known as Tmax) may help us better utilise them for suppressing oxidative stress after a meal.
Our recently published review looks at the effects of timing of phytonutrient intake on blood markers of oxidative processes after high fat and/or high carbohydrate (HFHC) mealtimes. We reviewed the existing literature where a solid form phytonutrient supplement was given before, with or after a HFHC meal and the resulting effects on oxidative stress were measured. The focus on solid form phytonutrients was selected because phytonutrients consumed in solid form have a fairly consistent Tmax window of around 1.5 to 3.5 hours after consumption [3].
We found that several circulating oxidative stress biomarkers were elevated following HFHC meals, including lipid hydroperoxides, soluble NADPH oxidase-derived peptide activity (sNox2-dp), 8-iso-prostaglandin-2α (8-iso-PGF2α), protein 47 phosphorylation (p47phox), Keap-1 protein, and nuclear NF-E2-related factor-2 (Nrf-2) DNA binding capacity. We also observed that, when the phytonutrient supplements were given either with or one hour before the HFHC meal, these biomarkers were suppressed, indicating a reduction in oxidative stress.
Our review highlights that supplementation with a solid form phytonutrient can suppress oxidative stress after a meal when the supplement is consumed with, or one hour before, a HFHC meal. These findings will inform a clinical research study to confirm the best time to consume phytonutrients to reduce oxidative stress after a meal.
Chronic exposure to oxidative stress
resulting from HFHC meals can increase the risk of chronic diseases such as
cardiovascular disease and some cancers. And while supplements can’t
replace a healthy and balanced diet, better understanding and optimising the
use of phytonutrients for regulation of oxidative stress represents a
potentially effective, convenient and safe approach to personal risk management
for chronic diseases associated with modern Western-style dietary
patterns.
By Margaret Murray
Dr Margaret Murray is a Teaching Associate in the Department of Nutrition, Dietetics and Food and Research Fellow in the School of Chemistry at Monash University. Her research investigates the health effects of food-based bioactives on chronic disease and mental health. Other interests include exploring how food systems can be tailored to support human and environmental health and teaching in the Master of Food Science and Agribusiness. Access Margaret’s research profile here.
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Publication information
Margaret Murray, Sophie Selby-Pham, Beau-Luke Colton, Louise Bennett, Gary Williamson, Aimee L Dordevic, Does timing of phytonutrient intake influence the suppression of postprandial oxidative stress? A systematic literature review. Redox Biol. 46 (2021) 102123, https://doi.org/10.1016/j.redox.2021.102123
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References
- K.H. Fisher-Wellman, R.J. Bloomer, Exacerbated postprandial oxidative stress induced by the acute intake of a lipid meal compared to isoenergetically administered carbohydrate, protein, and mixed meals in young, healthy men, J. Am. Coll. Nutr. 29 (4) (2010) 373–381, https://doi.org/10.1080/07315724.2010.10719854.
- F.J. Pashkow, Oxidative stress and inflammation in heart disease: do antioxidants have a role in treatment and/or prevention? Int. J. Inflamm. 2011 (2011), 514623, https://doi.org/10.4061/2011/514623.
- S.N.B. Selby-Pham, K.S. Howell, F.R. Dunshea, J. Ludbey, A. Lutz, L. Bennett, Statistical modelling coupled with LC-MS analysis to predict human upper intestinal absorption of phytochemical mixtures, Food Chem. 245 (2018) 353–363, https://doi.org/10.1016/j.foodchem.2017.10.102.
