ON THIS PAGE
- What is flax?
- Uses of flax
- What is flaxseed?
- Nutrients in flaxseed
- The best way of eating flaxseeds
- How much flaxseed can I eat per day?
- How flaxseed oil is processed?
- Culinary usage of flax seeds
- Health benefits of flaxseeds
- Flaxseed side effects
What is flax?
Flax is a plant that is native to Western Asia.
It has been used as early as 30,000 years ago. One of the earliest records of flax usage were in the Middle East by hunter-gatherers.
The first occurrence of cultivated flax was found in Syria 9,000 years ago.
The importance of the flaxseed plant in the development of humans
The word “line” is derived from the Latin or Greek word “linum”, which means “flax”.
Words such as linen, linear, lineage are derived from the world “line”.
Linum usitatissimum in latini means “flax most useful”
Flax is a plant belonging to the Linaceae family, which grows to about 3.5 feet high (just over 1 m), has blue flowers with five petals and fruit with the shape of a dry, spherical capsule.
The capsule of flax contains several flaxseeds.
- Flax has been used by hunter-gatherers, as long as 30,000 years ago in the Middle East
- Flax is not only useful for the nutritional value of the seeds but also for its fiber in textiles
Uses of flax
Flax is a crop with the following uses:
- Flaxseeds are used in the human diet for their many valuable nutrients and health benefits.
- Cosmetic industry uses linseed (flaxseed) oil in skin products, such as bath and cleansing products.
- Flaxseed oil is used in the production of paints, linoleum (floor covering), varnishes, wood finishing products and printing inks. (5)
- Linseed meal (a by-product of oil extraction) consists of 10% oil and a substantial amount of protein and, therefore, is a valuable feed for livestock, rabbits and fish.
- The flaxseed meal not only improves animals’ general and reproductive health but dairy, eggs and meat from flaxseed fed animals have a better fat composition, which is beneficial for human health.
- Yolks from hens’ eggs fed with flaxseeds have 30 times more linolenic acid and four times more Docosahexaenoic acid (DHA). (6)
- Flax fiber is soft, flexible, and stronger than cotton. The higher quality grade is used in weaving, linen production and damasks, while the coarser one is used in the production of ropes.
Flax is currently primarily known for its oil seeds. It is the third largest natural fiber crop and one of the five major oil crops in the world. (6)
The largest producers of flax are in order: Canada, China, U.S and India.
- Flax is a plant that is cultivated for its many uses: as food, in cosmetics, paints, linoleum, varnishes, weaving, oil production and livestock feed.
- Flax is one of the largest natural fiber and oil seed sources
What is flaxseed?
Flaxseed is also known as linseed, and sometimes written as flax seed. It is a glossy seed resembling an apple seed. Flaxseed is about 5mm in length and can come in brown or golden varieties.
The golden variety (solin) has a low omega 3 ALA fatty acid content and high omega 6 fatty acid content, so it is not valuable for human health. (7)
Flaxseed has a crisp and chewy texture and a slightly nutty, earthy flavor. It has several culinary uses.
Flaxseeds can be used whole, milled or ground, and as flaxseed or linseed oil.
It is the richest plant source of lignans, containing up to 0.7-1.5% of the dry weight of the seed.
Flaxseed seeds contain up to 28% fiber and the ratio of soluble to insoluble fiber varies between 20:80 and 40:60.
The total weight of the seed contains between 20-30% of protein.
Flaxseeds are 35-45% oil, of which 70% is Alpha-Lipoic Acid (ALA) (8).
Flaxseeds, just like chia seeds, have been popularized since the 1990s when omega 3 fatty acids became a focus of scientific studies.
- Flaxseed is a small seed resembling an apple seed
- It is the earliest crop used for oils and dietary fiber
- It is very rich in lignans, proteins, omega 3s and fiber
Nutrients in flaxseed
Flaxseeds are abundant in bio-active plant substances and is considered a functional food (foods with a positive effect on health beyond basic nutrition). (9). It consists of:
- Oils – mostly Alpha linolenic acid (ALA), but also oleic, linoleic, palmitic and stearic acids.
- Protein – globulins and glutelin, with an amino acid profile similar to soybeans and with no gluten. However, this protein is not considered complete, since it contains limited amounts of amino-acid lysine.
- Lignans (phenolic compounds) – contain up to 800 times more than other plant food.
- Dietary fiber – both soluble and insoluble, with proportions varying between 20:80 and 40:60.
- Soluble polysaccharides
- Vitamins – thiamine, niacin, vitamin B6, folate and choline
- Minerals – iron, magnesium, manganese, copper, phosphorus, selenium, zinc, calcium and potassium.
Flaxseed oils have an excellent omega 6 to omega 3 (0.3:1) ratio.
For more details, please see nutrition table of flaxseeds.
- Flaxseeds are considered a functional food, since they are rich in bio-active substances
- Flaxseeds are abundant in nutrients and antioxidants
The best way of eating flaxseeds
You can eat flaxseeds whole, ground, or as extracts, such as flaxseed oil or mucilage.
Note that the range of benefits and effects of flaxseed in the body depends on the form they are consumed, for example:
- Mucilage extract is the best form to treat specific conditions, such as constipation and irritable bowel syndrome, and is the most effective in lowering blood glucose levels.
- Flaxseed oil extract, on the other hand, has shown to be most effective flaxseed form in suppressing tumor cell growth.
- Consumption of whole seeds does not increase significantly the levels of ALAs in the blood plasma, while milled seeds and flaxseed oil provide significant increases of ALA in the body. (10)
- Due to the hard outer layer of flaxseeds, many nutrients are simply not released and end up extracted in the feces.
Freshly ground seeds
The widest range of benefits of flaxseed come from the freshly ground seeds. It is the cheapest and best way of getting most of the flaxseed’s many nutrients.
Flaxseed has a tough outer shell. Therefore, many nutrients trapped inside the seeds will simply pass through your body undigested.
Grinding flaxseeds makes the nutrients available for digestion and absorption.
HINT: buy flaxseeds in bulk and keep them in the freezer or refrigerator to extend their freshness. Ground only the amount needed per meal or per day. If you freshly grind more flaxseeds, keep them in an airtight container in the fridge or freezer.
- To obtain the most nutrients out of flaxseeds, with minimal unpleasant gastrointestinal effects, use milled seeds rather than whole seeds.
- For the greatest increase in ALA in your blood, use either flaxseed oil or milled flaxseeds.
- Grind the fresh flaxseeds before using them, for the maximum benefits.
How much flaxseeds can I eat per day?
Amounts smaller than 50 grams daily are used to avoid toxicity. (8)
Flaxseeds are rich in fiber. Therefore, if you are not accustomed to a high fiber diet, it is advisable to start with a smaller amount (e.g. 1 teaspoon of milled seeds) and gradually increase it to avoid abdominal discomfort.
Whole flaxseeds may cause adverse gastrointestinal effects in some people. In fact, the side-effects were so severe that some individuals affected had to be withdraw from the study. (10)
The consumption of milled flaxseed is gentler to the gastrointestinal system.
- Eat between 10-50 grams for the most optimal results.
How flaxseed oil is processed
Flaxseed oil for human consumption is extracted by cold press at below 95F (35C).
Due to the linseed structure of flaxseeds, oil extraction is more difficult than in other seeds and sometimes requires double pressing.
Flax meal is a by-product of oil extraction. It still contains about 10% oil.
The flax meal after the first oil extraction is then used for either oil-rich livestock feed or for further processing to extract the rest of the oil. (14)
- The cold press method is used to extract oil for human consumption.
- The by-product, flax meal, is then used for livestock feed.
Culinary usage of flax seeds
Flaxseeds are edible in many forms:
- Whole seeds
- Milled/ground seeds
- Flaxseed oil
- Mucilage extracts
- Alcohol extracts
- Flaxseed meal that has been partially defatted
- Flaxseed hulls
Although most benefits of flaxseeds are obtained from milled seeds, whole seeds have a nutty flavor and nice crunch, which is sometimes more suitable.
Flaxseeds can be sprinkled on almost any cold or hot food. However, be aware that some nutrients may be lost due to heating, so for maximum benefits don’t use them for cooking at high temperatures.
Lignans and fiber aren’t affected by heat. Therefore, adding flaxseeds to baked products, such as bread, allow them to retain their original lignans and fiber contents.
Here are some examples of how you can use flaxseeds in the kitchen:
- Sprinkle them on your morning cereal or fruit salad. For maximum nutrients mill them first, for a crunch use the whole seeds
- Add milled seeds to your smoothies
- Use in protein shakes, after training, for extra energy and protein
- Use in making bread or other baked products, such as cookies or muffins
- Garnish soups with whole seeds for a nutty crunch
- Add milled flaxseeds instead of breadcrumbs when making meatballs, burgers, or veggie burgers
Please note that to avoid oxidation and rancidity of the oil component of flaxseeds, blend the whole flaxseeds just before adding them to food. The easiest way is to blend them, is in the coffee grinder.
- Flaxseeds can be used in many forms for culinary purposes: whole, milled, flour, or as extracts (oil, mucilage)
- Flaxseeds are versatile in the kitchen and can be added to almost anything.
Health benefits of flaxseeds
Flaxseed’s popularity skyrocketed in the last two decades, primarily due to the association of omega 3 fatty acids with the prevention of cardiovascular diseases and other benefits.
Its exceptionally abundant nutrients have been also linked to many health benefits.
Studies on flaxseed’s health benefits have been naturally welcomed by flaxseed producers, media, and nutritionists. They quickly started to promote flaxseed products, blowing their benefits out of proportion.
Flaxseeds are abundant in nutrients and are potentially associated with many benefits. However, it is crucial to bear in mind that the science behind these health claims is still weak, and sometimes conflicting.
Omega 3 fatty acids, for example, which made this apparent superfood so popular, are in flaxseeds made of Alpha linolenic acid (ALA), which is not nearly as beneficial as other omega 3s, such as DHA or EPA.
There is definitely needs to be more, good quality clinical trials to confirm many of these benefits.
Nevertheless, while scientists are looking for more proof, it looks like the potential benefits of flaxseeds outweigh the side effects. Therefore, if the negative effects of flaxseed don’t apply to you, make this tiny seed a part of your heathy diet.
The article “Flaxseed benefits” reveals the evidence associated with flaxseed consumption. (coming soon)
- There are many potential flaxseed benefits, although the studies are still relatively weak
- If you are not negatively affected by flaxseeds, adding them to your healthy diet has many potential benefits
Flaxseed side effects
Flaxseeds and flaxseed oil are not in the Generally Recognized as Safe (GRAS) list (15), because there are not enough studies on long-term effects. Most studies, so far, generally show that it is safe to consume by a healthy population.
However, that there are some cases where flaxseeds and flaxseed extracts, such as oil, should be limited or avoided.
Here is a short summary of the side-effects of flaxseeds:
- Flaxseeds contain anti-nutrients (compounds that reduce the body’s ability to absorb nutrients, especially the unripe seeds).
- High fiber contents of flaxseeds may cause gastrointestinal problems and reduce the absorption of some nutrients and medications
- Flaxseeds can cause allergy and sensitivity reactions
- Flaxseeds may be unsafe during pregnancy and in some hormone related cancers
- Flaxseeds may interact with some blood pressure, diabetic or blood clotting medications
The evidence of some of these negative effects of flaxseeds is still weak and requires more studies. For a comprehensive list of studies, please see “Flaxseed side-effects” article.
- Flaxseed consumption is not yet approved by the FDA due to insufficient long-term studies, but generally is considered safe by most up to date studies.
- There are some side-effects that need to be considered, before adding these seeds to your diet.
- Some of the side-effects require more studies. Therefore, in the meantime, the consumption of flaxseeds should be considered on an individual basis.
NUTRITION FACTS VS NUTRITION MYTHS
You will find a summary of the most common nutrition myths and evidence-based nutrition facts here.