A: Chia and flax are typically added to equine diets as supplemental sources of omega-3 fatty acids. Both are rich in linolenic acid (ALA), which is a precursor to the longer chain fatty acids: ecosapentaenoic acid (or EPA) and decosahexaenoic acid (or DHA). Flax or linseed meal, the end product after fat extraction, has long been used in livestock feeds as a protein source. But more recently interest has built around the whole flax seed due to its potential impact of inflammatory conditions. Equine research has shown potential benefits in improving short-term insulin sensitivity, as well as reducing sensitivity to biting fly allergy. Other benefits might exist in mediating a number of inflammatory conditions.
A 2012 study by Ciftci et al published in the European Journal of Lipid Science and Technology showed that while whole flax seeds contained more total fat than chia (about 45% vs. 35%), the difference in omega-3 fatty acid content was small, with about 58% of the total fat being ALA in flax and 60% in chia. These percentages might appear higher than you see on product labels as products may express omega-3 and -6 as a percentage of the total product rather than as a percentage of the total fat. Chia had slightly higher omega-6 fatty acid content compared to flax (20.37% vs. 15.3%), giving chia an omega-6 to 3 ratio of 0.35:1 versus 0.27:1 for flax. This ratio is significantly lower than other common sources of fat in the equine diet, such as rice bran oil (21:1), soybean oil (7:1), canola oil (2:1), and corn oil (46:1).
What does this mean in real world terms? It means that every 100 grams of flax provides approximately 45 grams of total fat, 26 grams of ALA omega-3, and 6.8 grams of omega-6, whereas 100 grams of chia provides approximately 35 grams of total fat, 21 grams of ALA omega-3, and 7 grams of omega-6. Remember that these values will vary with cultivar (a plant variety that has been produced in cultivation by selective breeding) and growing conditions. While the fatty acid composition is where much of the attention is for these two seeds, they have other potential benefits, as well.
Both seeds provide natural vitamin E as mixed tocopherols (a family of vitamin E compounds naturally found in vegetable oils, nuts, fish, and leafy green vegetables), with the majority in the form of gamma tocopherol. Flax provides more total tocopherol than chia. Vitamin E is an important nutrient in the equine diet as it is a potent antioxidant. Flax and chia are both sources of beneficial, highly digestible fiber, and flax is a rich source of lignans, a type of phytoestrogen (an estrogen occurring naturally in legumes considered beneficial in some diets). While phytoestrogens occur in many plants, they can interfere with estrogen metabolism and this has caused some owners to move away from flax in favor of chia, which has lower lignan levels.
Another plus for chia is that it does not need to be ground. While many people successfully feed flax whole, the outer shell is hard and may not be fully broken down during digestion, which inhibits the horse’s access to the nutrients within. For this reason flax is commonly fed ground. Owners either grind the seeds and feed immediately to prevent oxidation of nutrients, or buy ground stabilized flax, which has a shelf life or anywhere from six month to two years, depending on the grinding process used.
A common misconception is that you must boil flax before feeding. This is because flax contains cyanogenic glycocides, which can be released as cyanide should they come in to contact with enzymes within the seed. The reality is that it is unlikely that harmful levels of cyanide are released due to the fact that the enzymes within the seed are denatured by stomach acid during digestion. Additionally, boiling the seeds would potentially have a negative impact on the omega fatty acids.
Whether whole or preground, flax is significantly cheaper than chia at about $0.65 per 100 grams for pre-ground flax versus $1.20 per 100 grams for chia. However prices can vary considerably. Generally, serving sizes for a 1,100-pound horse range from about 100 grams (4 ounces) up to a pound a day depending on the reasons for feeding.