Natural Health Products in Pregnancy: Improving Generational Health

The fascinating emerging field, the “fetal origins of adult disease,” describes the impact that environmental factors in utero can have on the long-term health of the offspring.^[1] For instance, birth weight and other measures of fetal growth, as well as maternal stress during pregnancy, have been associated with risk of chronic adult disease, including cardiovascular and metabolic disease.^[2][3] Recent science shows that select natural health products can also reduce the baby’s long-term risk of disease.

The best example of the developmental effects of nutrients is folic acid. Folic acid decreases risk of neural tube defects.^[4] In addition, the use of a multivitamin during pregnancy furthermore reduces the risk of five other birth defects including heart defects, as well as three childhood cancers including leukemia and pediatric brain tumours.^[5][6] We advocate the use of a vitamin A/ beta-⁠carotene–free multivitamin, considering the teratogenicity of vitamin A together with its low RDA in pregnancy (2500 IU), which is easily obtainable from food alone; vitamin A deficiency is virtually nonexistent in North America.^[7][8][9]

Docosahexaenoic acid (DHA) is well-known for its beneficial effects on neurodevelopment.^[10] DHA is a major component of the phospholipid bilayer membrane in neurons, and in the third trimester there is a rapid increase in the proportion of omega-⁠3 fatty acids in the fetal brain, retina, and liver.^[11] DHA is implicated in the development of synapses or communication junctions between brain cells, neurotransmitter metabolism, and retinal development.^[12] Studies have shown that fish oil supplementation during pregnancy improves measures of intelligence in children, including mental processing, hand and eye coordination, and problem-solving.^[13][14][15] Fish intake during pregnancy has been associated with higher verbal IQ, social behavior, fine motor, communication, and social development scores.^[16]

Eicosapentaenoic acid (EPA) is often overlooked in this setting; however, given the prevalence of mood disorders during pregnancy or postpartum, it is important to coadminister EPA with DHA due to its mood-enhancing effects.^[17] Several meta-analyses have demonstrated that an oil with a 2:1 ratio of EPA:DHA or higher is necessary to obtain antidepressant and mood-stabilizing effects, and that higher EPA is associated with better antidepressant effects.^[18][19] EPA may also improve the impact of DHA, as it has also been shown to upregulate fatty acid–transport proteins in the placenta, thereby increasing fetal transfer of DHA.^[20] A 2:1 ratio of EPA:DHA is therefore an ideal type of fish oil for supplementation during pregnancy.

Fish oil during pregnancy has also been shown to reduce the risk of allergic disease in the offspring.^[21] This includes risk of eczema, asthma, and allergy. Supplementation of between 2 and 4 g combined EPA and DHA has been associated with an increase in the number of T regulatory cells, cells that are involved in dampening an overactive immune response.^[22] Similarly, fish oil has been associated with a decrease in the incidence of food allergy and eczema,^[23] and with a reduction in the risk of asthma at age 16 years.^[24]

Probiotics are like adaptogens for the immune system. They can boost the immune response if impaired, but they can also promote the induction of tolerance. Multiple human trials have shown that maternal use of a probiotic in the last three to six months of pregnancy, as well as delivery to the baby in the first six months of life, can dramatically reduce the development of eczema, asthma, and allergy.^[25][26] A recent meta-analysis examined 17 studies, including 4755 children, and found that supplementation with probiotics during pregnancy and early infancy was associated with a 22% lower risk of eczema compared to untreated infants, and this was especially marked in children who received a mixture of probiotics;^[27] these children had an almost 50% reduced risk. Another meta-analysis found that probiotic supplementation during pregnancy and early infancy may reduce risk of atopy as well as food hypersensitivity in the infants.^[28]

The mechanism for this effect appears to be related to uptake of probiotic species from the maternal gut. An intriguing new discovery is that the placenta harbors a unique microbiome.^[29] In addition, during late pregnancy and lactation, a bacterial enteromammary (“gut-breast,” if you will) pathway is established, through which specialized immune cells select specific bacteria from the maternal intestinal tract, chaperoning them through the bloodstream to the mammary gland, where they enter the breastmilk and colonize the infant gut.^[30][31]

Observational data suggests that maternal vitamin D status is associated with lower risk of wheeze and better response to treatment (i.e. bronchodilator effect) in the offspring.^[32] A meta-analysis of cohort data found that the lowest risk of childhood asthma was associated with maternal 25(OH)D levels of 70 nmol/L.^[33] Data from a large cohort study of cod-liver oil supplementation in pregnancy, which contains omega-⁠3 fatty acids plus vitamin D, indicates that supplementation is associated with 70% reduced risk of type 1 diabetes in the offspring.^[34]

Other data suggests that maternal vitamin D deficiency leads to increased fetal exposure to hormones called glucocorticoids such as cortisol (the “stress hormone”), which can affect programming of the fetal brain in regards to regulation of the stress response (HPA axis) and can impact fetal growth in utero.^[35][36]

In conclusion, pregnancy is a particularly sensitive window during which long-term health outcomes can be determined. There is ample evidence to justify the prenatal supplementation of specific nutrients, which include folic acid and a multivitamin, an EPA- and DHA-containing omega-⁠3 fatty acid supplement, a multistrain probiotic, and vitamin D.

REFERENCES

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