Hemp Seeds Rival Soybeans in Protein Quality

Newsdate: Mon, 19, Jan 2015 - 07:00 am

Soybean meal is the most commonly added protein source in horse feeds. However, increasing numbers of horse owners are shying away from feeding it, most commonly because of allergic reactions.

Dry hemp seeds before harvest

Dry hemp seeds before harvest

The protein in hemp seeds is comparable to that in soybeans and, in many cases, exceeds the EAA content of the animal protein, whey, found in milk.
© 2015 by D. Kuru

Most soybeans grown in the U.S. have been genetically modified, which is a concern for many. Furthermore, it is difficult to ascertain from a feed label if the soy product has been heat-treated (necessary for inactivating trypsin inhibitor found in raw soybeans). Finally, soy contains significant levels of phytoestrogens, which may influence behavior, affect breeding, or interact with other hormones.

The good news about soybeans is their protein quality -- it compares favorably to protein found in animal sources. But there are other good choices, the most promising of which is hemp seed.

Understanding protein quality

Proteins are long, complex chains of amino acids. Once protein is digested, the amino acids travel to tissues, where they are “reassembled” into proteins specific to that particular part of the body, assuming all of the building blocks (amino acids) are available. Your horse can synthesize some amino acids, but there are 10 that your horse cannot produce, or cannot produce in adequate quantity, and therefore, they must be in his diet (listed in Table 1). These are referred to as essential amino acids (EAAs).

Most feeds contain some protein, and therefore, some EAAs, but if any EAAs are present in low amounts, they limit the extent to which the others can be utilized, resulting in leftover amino acids. And, unfortunately, amino acids cannot be stored to be used later. Instead, they are dismantled by the liver, putting strain on the kidneys to remove urea, and contribute to excess calories and even glucose production.

Hemp seeds

A relatively new food to western cultures, hemp seeds have exceptional protein quality. Their two main proteins are albumin and edestin, both of which have significant amounts of all EAAs. The protein in hemp seeds is comparable to that in soybeans and, in many cases, exceeds the EAA content of the animal protein, whey (found in milk), as shown in Table 1.

Table 1: Essential Amino Acid (EAA) Comparison between Hemp seeds, Soybeans, and Whey (grams per 100g)1

EAA

Hemp seeds

Soybeans

Whey

Methionine

0.58

0.53

0.23

Arginine

3.10

2.14

0.39

Threonine

0.88

1.35

1.02

Tryptophan

0.20

0.41

0.25

Histidine

0.71

0.76

0.29

Isoleucine

0.98

1.62

0.85

Leucine

1.72

2.58

1.40

Lysine

1.03

1.73

1.15

Valine

1.28

1.60

0.91

Phenylalanine

1.17

1.78

0.49

Hemp seeds rival soybeans as an ideal protein

What’s even more impressive, however, is the ratio of each EAA to the lysine level – a true measure of protein quality. With horses, quality is determined by comparing each EAA to lysine as it would exist in muscle2. Lysine is assigned a value of 100. The ideal values are shown in Table 2, which reveals how every EAA found in hemp seeds surpasses the ideal ratio beyond soybean’s ability.

Table 2: Ratios of EAAs to Lysine, Compared to Ideals3

EAA

Hemp seeds

Soybeans

Ideal

Methionine

56

31

27

Arginine

301

124

76

Threonine

85

78

61

Tryptophan

n/a

n/a

n/a

Histidine

69

44

58

Isoleucine

95

94

55

Leucine

167

149

107

Lysine

100

100

100

Valine

124

92

62

Phenylalanine

114

103

60

Hemp seeds are easy to find in stores that sell whole foods. Horses enjoy their palatable, nutty flavor. Adding ½ cup (providing 25 grams of protein) to your horse’s daily ration will boost the overall protein quality of his diet.

Hulled (shelled) hemp seeds can be expensive, however. A more economical option is to buy whole hempseeds and grind them yourself. To obtain the same level of protein, measure approximately twice the volume.;

Bottom line

Domesticated horses cannot easily enjoy the variety of feedstuffs a natural setting provides. Even the healthiest grass pasture may not meet every nutrient requirement. Offering whole foods such as hemp seeds on a regular basis gives you another option for meeting your horse’s protein needs.

Juliet M. Getty, Ph.D. is an internationally respected, independent equine nutritionist who believes that optimizing horse health comes from understanding how the horse’s physiology and instincts determine the correct feeding and nutrition practices. She is available for private consultations and speaking engagements.

Dr. Getty’s comprehensive resource book, Feed Your Horse Like a Horse, is available at Dr. Getty’s website, www.GettyEquineNutrition.com, as well as from Amazon (www.Amazon.com) and other online book retailers. The seven separate volumes in Dr. Getty’s topic-centered “Spotlight on Equine Nutrition” series are also available at her website (where Dr. Getty offers special package pricing) and from Amazon (in print and Kindle versions) and from other online retailers. Dr. Getty’s books make ideal gifts for horse-loving friends.

Dr. Getty’s website, www.GettyEquineNutrition.com, offers a generous stock of free, useful information for the horseperson. Sign up for her free monthly newsletter, Forage for Thought; browse her library of reference articles; search her nutrition forum; and purchase recordings of her educational teleseminars. Reach Dr. Getty at gettyequinenutrition@gmail.com.

1.  Callaway, J.C. 2004. Hempseed as a nutritional resource: An overview. Euphytica, 140. Pages 65-72. Printed in the Netherlands.

2.  National Research Council. 2007. Proteins and amino acids. Nutrient Requirements of Horses, Sixth Revised Edition. Washington, D.C.: The National Academies Press. Pages 64-65.

3.  Hemp seed and soybean values were calculated by dividing each EAA level by its lysine level (1.03 for Hemp seeds; 1.73 for Soybeans; shown in Table 1)

by Juliet M. Getty, Ph.D.

About the Author

Flossie Sellers

As an animal lover since childhood, Flossie was delighted when Mark, the CEO and developer of EquiMed asked her to join his team of contributors.

She enrolled in My Horse University at Michigan State and completed a number of courses in everything related to horse health, nutrition, diseases and conditions, medications, hoof and dental care, barn safety, and first aid.

Staying  up-to-date on the latest developments in horse care and equine health is now a habit, and she enjoys sharing a wealth of information with horse owners everywhere..

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