This article originally appeared in the NAHA Journal (Fall 2019) and it is republished here according to the NAHA Writer Guidelines 2019-20 copyright statement.
By Kathy Sadowski, MS in Aromatherapy, RA, LMT
Answering the question “What is the difference between a seed and a nut?” can become quite complex. This is because the culinary lingo for the word “nut” is not the same as the botanical definition. Thus, many plants that you would think of as having a nut, actually have drupes or legumes, such as with almonds and peanuts respectively.
Seeds can be confusing as well. While many edible seeds come from plants of the Poaceae family, the list can include plants from many other families as well.
Finally, as an aromatherapy professional, it is important to know the difference between an essential oil and a carrier oil. Many seeds, nuts, drupes, and legumes are non-aromatic, but can be pressed or extracted to make a carrier oil with valuable benefits. The last section will provide a listing of carrier oils made from these plant parts.
Nut are hard shelled fruits that contain 1 or 2 seeds. When the fruit dries, the ovary wall hardens, while the seed remains unattached or free within the ovary wall. The hard outer shell is not eaten, and must be cracked off from the fruit. Nuts belong to the plant order Fagales and the plant families Fagaceae or Betulaceae, but not all species produce true nuts.
The botanical definition of a nut, as listed above, differs from the culinary identity of a nut. The culinary perspective of a nut includes edibles that may actually be seeds, drupes, or legumes, and are not technically nuts.
List of True Nuts: Beach, Chestnut, Hazel, and Oak
A seed is a small embryonic plant enclosed in a seed coat, which has stored food to nourish the embryo as it grows into a plant. This embryo is a fertilized ovule (2). Some seeds require their outer husks to be removed before eating.
Many of the seeds that we eat come from plants that are considered grains or pseudo-cereal grains. However, there are several exceptions.
Grains or cereals are the edible seeds from a plant in the family Poaceae. These plants have jointed and hollow flower stems with nodes where the leaves are found (1). Seeds from this plant family must be husked and cooked before eating in order to be digestible. The grains are often eaten as a hot cereal or ground into a flour.
Seed examples: Barley, Corn, Millet, Oats, Rice, Rye, Spelt, Wheat
Plants of the Cymbopogon genus also belong to the Poaceae family, and include lemongrass (Cymbopogon citratus), citronella (Cymbopogon nardus), and palmarosa (Cymbopogon martini). While these plants’ seeds are not typically eaten, the aromatic grass is very useful and often made into essential oil.
These are seeds that resemble a cereal, but are not a part of the Poaceae family.
Examples of Pseudo-cereal Seeds: Buckwheat, Chia, Flax, Sesame, Quinoa
Buckwheat (Fagopyrum esculentum) belongs to the Polygonaceae family that also includes mountain sorrel (Oxyria digyna), rhubarb (Rheum rhabarbarum) and plants of the dock (Rumex) genus. Seeds are ground into a flour.
Chia seeds come from the plant Salvia columbariae, in the Lamiaceae family. The seeds are very hydrophilic, meaning they absorb large amounts of water. Soaked seeds become extremely mucilaginous with a thickening gel like texture.
Flaxseeds come from the plant Linum usitatissimum of the Linaceae family. Like chia seeds, flaxseeds are mucilaginous and form a thick gel when soaked in water.
Sesame seeds comes from the plant Sesamum indicum of the Pedaliaceae family. Seeds can be roasted and eaten, or cold pressed into a quality carrier oil.
Quinoa comes from the plant Chenopodium quinoa of the Amaranthaceae family. It is in the same family as spinach. Quinoa is a valued gluten free pseudo-cereal grain containing 9-16% protein, and valuable nutrients and phytochemicals (3).
These include seeds from plants that are not grain-like.
Examples of Non-grain Seeds: Cocoa Bean, Coffee Bean, Pomegranate Seeds, Poppy Seeds, Pumpkin Seeds, and Sunflower Seeds
Drupes include all members of the genus Prunus in the family Rosaceae, as well as some other flowering plants and palms. These stone fruits have a pulpy exterior surrounding a hard shell that contains a seed. Drupes include: peaches, plums, almonds, pecans, walnuts, and coconuts. In the case of peaches, the pulpy part is eaten, while in the case of almonds and pecans, the seed part is eaten.
List of Drupes
Legumes are all plants of the Fabaceae family, and have pods containing multiple fruit. A pulse is a term used to describe the dried edible seeds of legumes. Plants of the pea family (Fabaceae) have irregular flowers that form into pea like pods.
List of Legumes
Many carrier oils used in aromatherapy are extracted from the seeds, nuts, drupes, or legumes of plants. It is important to notate the difference between an essential oil and a carrier oil. An essential oil is most typically steam distilled and only contains the lightest, most volatile molecules.
A carrier oil is pressed, macerated, or solvent extracted. Typically, the cold pressed or expelled oils are best, as heat can destroy some nutrients (4). Refined carrier oils have had components removed to change the color, odor, taste, or texture. Refining typically involves the use of high temperatures or chemicals, and valuable nutrient content can be lost (4).
Essential oils are highly volatile and chemically reactive. Thus, it is recommended that they be diluted in a carrier oil for topical use. The standard dilution guideline for all over the body use is 2%; that is about 10-12 drops of essential oil in one ounce of carrier oil. This dilution would be higher with children, the elderly, and sensitive skin.
Plant Part: The drupe kernel is pressed. The cold pressed extraction method is preferred (4)
Oil Description: Sweet almond oil is very light and typically has a long shelf and mild aroma. It is an excellent carrier oil used in aromatherapy, penetrating easily into the skin.
Plant Part: The drupe kernel is preferably cold pressed (4).
Oil Description: Apricot kernel oil is light, mild, and easily absorbed without leaving a residue on the skin.
Plant Part: The fleshy portion of the fruit, which is technically considered a berry, is pressed.
Oil Description: Cold pressed and unrefined oil is greenish in color. Refined oil is yellow. Oil is thick and good for dry skin.
Plant Part: Seeds are pressed, with lower grades being hot pressed and solvent extracted (4).
Oil Description: Castor oil has a very thick texture, with a mild aroma, and unpleasant flavor. It has been used as a purgative internally, and as a thick skin protectant topically.
Plant Part: Fermented seeds are roasted and hot expressed or solvent extracted (4).
Oil Description: Unrefined oil is strongly aromatic with the smell of chocolate. Refined oil does not have an aroma, but less nutritional value. The oil is creamy and thick, and the unrefined type is a rich source of vitamin E and antioxidants. It is nourishing and protective to the skin and melts at skin temperature.
Plant Part: The drupe’s white inner flesh is cold pressed, or the seed can be boiled, pressed, or solvent extracted (4). Fractionated coconut oil is light and liquid at room temperature, but contains less valuable nutrients.
Oil Description: Unrefined oil is solid at room temperature and nourishing to skin and hair. It has a mild coconut aroma and a good shelf life. It also has a lathering effect when added in soap recipes. Refined oil is very light, non-aromatic, and has an even longer shelf life.
Plant Part: Seeds are hot-pressed, often including solvent extraction, and extracted oil is often refined to improve color and flavor (4).
Oil Description: Oil is non-greasy, absorbs easily, and is helpful to damaged skin. It has a mild grape-like flavor and scent that is easily neutralized in aromatherapy and culinary recipes.
Plant Part: Seeds are cold-pressed
Oil Description: Hemp seed oil is greenish, with a mild nutty flavor and aroma. High in poly-unsaturated fats, this oil can go rancid easily, and should be kept refrigerated and not heated to maintain its significant nutritional value.
Family: Simmondsiaceae (2)
Plant Part: The seeds are cold pressed, filtered, and then pasteurized to form a wax. Refined varieties are bleached, removing the color and aroma (4).
Oil Description: Unrefined oil is golden, with a mild aroma, and very long shelf life. Its consistently is similar to our own skin’s sebum, making it easily absorbed (2). Stored at cold temperatures, it may solidify or become cloudy, but will normalize again at room temperature. Jojoba oil is a good non-greasy oil for use on the face or hair, and with sensitive or dry skin.
Plant Part: Flesh of the drupe is fermented, pressed, and filtered. First pressed oils are considered extra virgin. Then, drupes are pressed again, to produce a lesser quality olive oil.
Oil Description: Olive oil is widely used in skin and hair care products as well as culinary recipes. Non-refined oil has a rich flavor, strong aroma, thick consistency, and yellow-green color.
Plant Part: Oil is extracted from the fruit flesh or the kernel. Fruit flesh oil is quite different from kernel oil, with kernel oil being preferred in the soap industry.
Oil Description: Avoid use. Excessive planting of palm as a crop has led to significant biodiversity loss in Southeast Asia (5). Plant and animal habitats are greatly affected (6). Further impacts include deforestation, water pollution, soil erosion, air pollution, and unfair labor practices (5).
Plant Part: Legume flesh is pressed.
Oil Description: The oil is very nutty in aroma and oily in texture. Avoid with allergies to peanuts.
Plant Part: The seeds are dried and cold pressed.
Oil Description: The oil is greenish orange in color with a slightly sweet taste. It is nutritious and great for dry or damaged skin. Refrigeration is recommended for this oil that is high in omega fats.
Plant Part: Seeds are cold pressed.
Oil Description: The yellowish colored oil is comprised of unsaturated fats that help condition the skin and hair.
Family – Pedaliaceae
Plant Part: Hulled seeds are cold pressed and filtered. Lesser quality oils are hot processed and possibly refined (4).
Oil Description: Oil is yellow colored, with a light nutty flavor, and a good shelf life. It is skin protective and softening.
Plant Part: Fruit pulp
Oil Description: Avoid use to aid in species preservation. The plant is listed on the IUCN Red List of Threatened species as vulnerable (7).
Plant Part: Seeds are cold pressed or lesser qualities could be solvent extracted (4).
Oil Description: The oil is light, sweet, absorbs easily into the skin, and is softening and moisturizing. Sunflower oil has a good shelf life if stored properly.
Plant Part: The wheatgerm is separated from the grains, and then pressed / macerated. Solvent extraction and hot pressing are sometimes used (4).
Oil Description: The oil is extremely thick, protective, and nourishing for dry skin. Wheatgerm is rich in proteins, vitamin E, vitamin K, and fatty acids, with significant antioxidant and antibacterial activity (8). Avoid with wheat allergies.