Should we be moving towards using Micronutrient Ratios?
Micronutrients as Ratios
All diets require large amounts of macronutrients: proteins, carbohydrates and fats; in addition to small amounts of micronutrients: vitamins and minerals. The failure to maintain the correct amount of micronutrients in our diet will almost certainly lead to deficiencies and disease.
The foundation of nutritional science is based on specific foods, nutrients or other compounds on their own. A great deal has been learned from human studies with single nutrients; especially as a means to treat nutrient deficiencies in many parts of the world, however todays science is shifting towards the diet as a whole and dietary patterns rather than single nutrients.
It is believed that there may be optimal physiological combinations of nutrients, which can be termed micronutrient ratios. Hence, advising the ratios of nutrients in a complete diet is predicted to be more informative than each single nutrient on its own. Traditionally, intake values for all vitamins or all minerals have not been presented relative to each other and there are no defined recommendations for a person’s total daily intake of micronutrients. The authors of a recent paper published in Nutrients have devised a nutrient ratio hypothesis based on the following possibilities:
no person consumes a single nutrient (macro- or micro-nutrient) separately in a meal.
in an ideal varied diet, the nutrient intake would be different for each eating occasion.
nutrients do not target one particular tissue when consumed.
at the molecular level, nutrients are multitaskers; each nutrient does not act in one specific metabolic pathway, or alone.
Why Dietary Micronutrient Ratios Are Important
It is thought that nutritional science must develop new standardised models to account for the complexity of human nutrient metabolism and lead to bridging the gap between single nutrient based information and studying micronutrients in relation to one in dietary patterns. This hypothesis has come about due to the fact that micronutrients are rarely, if ever, consumed separately. Furthermore, they are not tissue specific in their actions and at the molecular level they are known to work together. Already health status can be assessed by simple ratios, such as the waist hip ratio, the ratio of fat mass to lean mass, the ratio of sex hormones, the ratio of electrolytes, or the glucose to insulin ratio. All of these ratios provide more information than the components individually. Certain nutrient ratios already exist, such as the omega-6/omega-3 fatty acid ratio, the sodium/potassium ratio, the calcium/magnesium ratio and the eicosapentaenoic acid/arachidonic acid ratio.
Hence, different diets and ratios of dietary components and thus different levels of nutrients and their ratios may be an important consideration in chronic disease. Also, the status of micronutrients within different tissues and cells represents a large research gap for nutritional science. The interactions that occur between minerals, vitamins, genes and nutrients after ingesting food highlight the complexity of nutritional science and may be ultimately determined by the ratios of dietary micronutrients.
Data from the National Health and Nutrition Examination Survey (NHANES) has shown that the Western diet has a disruption in the ratios of micronutrients, due to the results showing that diets were chronically insufficient in calcium, magnesium, potassium, and vitamins A, D and E, but were higher in phosphorus, sodium and many of the B vitamins. It is possible that studies focused on one mineral or vitamin, while discounting the nutrient-nutrient interactions and that nutrients work together, may be one of the reasons results from nutritional trials are so wide-ranging.
Every micronutrient has a Dietary Reference Intake (DRI), which is a daily total micronutrient recommendation. However, it is believed that dietary micronutrient ratios should be routinely reported and that an effort be made to develop the framework and mathematics to allow strong correlations to health and disease outcomes. This nutrient ratio concept also proposes that there may be an ideal daily ratio of micronutrients to maintain health and prevent chronic disease, which would ultimately be related to certain dietary patterns, as opposed to DRIs.
Micronutrient Ratios
Micronutrient intake data, from food only, was assessed from NHANES, and together with DRIs, was used to generate initial micronutrient ratios. This research shows that the male and female dietary micronutrient ratios from food, not supplements, do not match those from the DRIs.
Mineral Ratios: Examining micronutrient patterns leads to the elucidation of a different picture of diet quality. For minerals, the most obvious difference between recommendations and intakes is the potassium to sodium ratio, where for 50–59 year olds, the DRI for potassium to sodium ratio is 4/1, whereas the Daily Value (DV) has a ratio of 2/1. These results imply that the minerals potassium and sodium are being consumed in the wrong ratio in the US diet, if we use the DRIs and DVs as the standard. Utilising ratios may also add more perspective to DRIs, as an incorrect ratio of mineral intakes may explain why cardiovascular disease (CVD) risk is associated with Ca supplement use. The increased intake of Ca may be affecting the ratios of other minerals and perhaps their physiological actions. The recent associations between a high phosphorous intake and all-cause mortality and CVD may be due to a disruption in the ratio of phosphorous to other nutrients. Furthermore, the ratio of calcium to magnesium is well known and recent epidemiological evidence suggests it may be important to determine the ideal ratio to reduce mortality and reduce the risk for postmenopausal breast cancer. Mineral research may benefit by investigating ratios on health outcomes as opposed to individual mineral levels. However, it may well be that optimal mineral ratios are specific for sex, age and also disease.
Vitamin Ratios: For vitamins, the differences in ratios between DRIs, DVs is less noticeable. The fat-soluble vitamins account for only 13% (16 mg) of the overall total daily intake for males and 14% (16 mg) for females. However, it has been shown that the intake of fat soluble vitamins is chronically insufficient in the US diet. Similar to the minerals, vitamin ratios may help explain why the DRIs are at their current levels. The importance and use of vitamin ratios is yet to be discovered, although ratios of smaller numbers of vitamins may provide some information regarding how vitamin ratios affect metabolism and health outcomes.
Conclusions
Examining ratios of micronutrients may deliver more information about how diet and health outcomes are related. Data shows that dietary ratios of micronutrients show some differences between intakes and recommendations. Further studies should be undertaken with a goal for it to be used in nutritional epidemiology and in nutritional research, rather than focusing on individual nutrient intakes. However, for future studies, nutritional scientists may have to consider the ratio of micronutrients in the diet, or evaluate blood and tissue by chemical analysis, before arriving at conclusions.
References
Kelly OJ. et al. (2018) Utilizing Dietary Micronutrient Ratios in Nutritional Research May be More Informative than Focusing on Single Nutrients. Nutrients. Jan 19;10(1)