Research efforts are ongoing to establish what potential nutritional differences exist between organic and conventional foods. In a recent study, the first long-term organic diet intervention study that we know of, as well as the first to include pregnant women while measuring these variables, showed that organic produce in individual’s diets significantly reduces exposure to pyrethroid insecticides. This is important because a growing body of research is showing links between pesticide exposure and poor neurodevelopment and cognitive development in children. Considering the common limitations of dietary intervention studies, this research was considered long-term because it lasted 6 months through two trimesters of pregnancy for the participants, who were compared across the same socioeconomic level (2). This study helps us add to the “pro” column for organic foods, especially when we think about the possible negative effects exposure to pesticides and insecticides may cause.

This image from the study mentioned above illustrates the concentration of  certain pesticides found in samples taken from the participants monthly throughout the second and third trimesters of their pregnancy. 3-PBA, a pesticide, is significantly higher in participants who consumed conventional foods when compared to the organic group(2).

This conclusion, quoted directly from the results of another recent study, aptly summarizes the potential downfalls of conventional foods when compared to the alternative of organic food:

“Current-use antibiotics and pesticides were undetectable in organic but prevalent in conventionally produced milk samples, with multiple samples exceeding federal limits.”(3)

This study is fascinating as researchers sought to find if a difference in contaminants could be identified between organic vs. conventional milk samples from across the various regions of the United States. Antibiotics such as Amoxicillin, Sulfamethazine and Sulfathiazole were detected in several of the conventional milk samples that exceeded federal limits. Also, bovine growth hormone and insulin like growth factor 1 were much higher in the conventional milk samples.

While federal limits and regulations are intended to protect us from these dangers, being an informed consumer can empower your decisions and help you know what to be aware of when it comes to choosing between organic and conventional options. Also, rules and regulations are not always adhered to.

Grain fed vs. Grass-fed

Omega-3 Fatty Acids & Other Nutrients

Studies show that consuming red meat from grass fed animals as part of the habitual diet can significantly increase consumer plasma and platelet long chain omega-3 fatty acids.This is due to the diet of grass-fed animals being slightly higher in omega-3 containing foods, such as nuts, seeds, and forage or pasture. Moderate doses of omega-3 fatty acids significantly decrease risk of heart disease(4,5) and is known to possess anti-inflammatory benefits. Eating less processed grain products or fewer grains as a whole in one’s diet can reduce the risk of heart disease in humans, too. Grass-fed animals are shown to have biomarkers indicative of health and wellness, which can translate to the food on your plate, mouth and body. You can check out a good article about the evidence-backed benefits of grass-fed beef in an article by Lily Nichols RDN here:

7 Reasons Grass-fed Beef is Worth the Money. 

While this study measuring omega-3 levels is almost 20 years old, the trend it illustrates is upheld by current research. The other two images here are from studies over the years which add to the growing body of research showing nutrient differences and vitamin content between grain-fed and grass-fed animals.

Do grass fed foods have less omega-6 fatty acids? Why is this good or bad if so?

Science supports no significant change to the overall concentration of omega-6 fatty acids between feeding regimens (those allowed to graze on grass vs. feed). However, since grass-fed beef consistently shows a higher concentration of omega-3 fatty acids as compared to grain-fed contemporaries, it creates a more favorable omega-6 to omega-3 ratio(6,7).  The importance of this ratio is summarized well by the following quote:

“A healthy diet should consist of roughly one to four times more omega-6 fatty acids than omega-3 fatty acids. The typical American diet tends to contain 11 to 30 times more omega -6 fatty acids than omega -3, a phenomenon that has been hypothesized as a significant factor in the rising rate of inflammatory disorders in the United States”(6).

While the data does not show a clear food safety advantage to grass-fed products over conventional products, the differences in quality and nutrient density of the meat itself show that based on quality standards, it is likely that grass-fed products will have a higher nutrient quality than grain-fed counterparts(8).

The health of the animal and the health of your food

When delving into the science behind grass-fed and grain-fed animals, it is almost disturbing to see what grain-fed animals experience.

“Liver abscess disease was the main cause of loss in grain-fed cattle”(9). 

The liver is the organ of the body (both human and animal) that plays a major role in removing waste products as well as using protein to improve fat metabolism. If the livers of our grain-fed food are failing, what does that indicate about our food, and ultimately, how can it affect our health as humans consuming these products?

Research investigating exactly those questions is ongoing, but data on the results of aggressive grain-feeding programs have produced the following information(10):

What are grain fed feeds made of? 

Feed grains can be composed of barley, grain sorghum, rye, corn, oats, wheat, forage and hay, and rice(11). These feeds are generally treated with antibiotics, and are used primarily for beef and dairy cows (10, 12).

How does the grain-feed cause disease?

The liver abscesses are bacterial infections associated with animals on aggressive grain-feeding diets (11). The infection causes damage to the cow’s stomach and allows disease causing bacteria to pass out of the stomach and onto the liver, where abscesses form, indicating a progression of disease state in the animal (12). In my experience seeing pediatric patients with fatty liver disease, a large contributing factor is a diet high in processed grains and sweets (both of these break down to sugar ultimately in the body). I am curious to know if there are more similarities than we know between animals and humans on diets composed primarily of processed grains/sugar and health outcomes.

What about “grass-fed” dairy?

Studies show that (certain conditions allowing) dairy products from grass-fed animals can improve the milk’s fatty acid profile (13). Grass-based diets have been shown to enhance precursors of fatty acids and vitamins with antioxidant properties, both of which are crucial to a healthy diet and lowering risk of disease (6).

Pasture Raised and Free Range

The following quote sums up the effect of pasture-raised animals well: “…the animal’s diet remains a key mechanism by which its nutrition and processing characteristics can be altered. Pasture feeding has been demonstrated to have a positive impact on the nutrient profile of milk, increasing the content of some beneficial nutrients” (14). In the case of hens, however, those raised in pasture can naturally obtain varying levels of nutrition as their forage time can be variable. Most hens require supplementation to make their diet complete. Their feed may be fortified, for example, with protein, vitamins, and/or minerals so that they can produce good quality eggs with more desirable characteristics(15).

As opposed to pastures with few plant species and feedlots, health is enhanced when animals graze phytochemically rich mixtures of grasses, forbs, shrubs, and trees. Diverse plant communities are nutrition centers and pharmacies that enable health…” (16).

Summary of Nutrient Quality Comparisons

Click here to download the FREE pdf version of the following chart.

Chart based upon references listed at end of article (13-28).

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