Health benefit of flaxseed ( Linum usitatissimum ): a mini review

The importance of nutrition and its impact on human well - being has increased interest in "functional foods." This has prompted a reevaluation of the practical advantages offered by various conventional food sources. it is the richest known source of alpha - linolenic acid (ALA), phytoestrogen lignans, and solubility fiber, flax continues to acquire popularity as a functional food and is currently gaining attention in the field of cardiovascular disease. Secoisolariciresinol diglucoside, a lignin derivative found in flaxseeds, is metabolized into mammalian lignans. Lignans have numerous biological effects. Flax lignans have an effect on the early warning indications of breast and colon carcinogenesis in animal models. Regular flaxseed consumption may affect total and low - density lipoprotein levels in the blood. Increase serum levels of the omega - 3 fatty acids ALA and eicosapentaenoic acid, reduce inflammatory markers, and reduce postprandial glucose absorption. Flaxseed has demonstrated significant antioxidant and anti - inflammatory properties in both animal and human research. In cases such as cardiovascular risk, certain types of cancer, and other metabolic disorders, a flaxseed supplement in the diet may be beneficial. Numerous studies have demonstrated the benefits of fresh flaxseed and flaxseed - based baked goods for maintaining health and preventing disease. This article focuses on the 'nutraceutical' potential of 'flaxseed' and its function as a 'medicine food' that is both therapeutic and preventative.


Introduction
Due to the prevalence of various degenerative lifestyle disorders, maintaining a healthy lifestyle in the modern world is challenging (Khalid et al., 2022).Due to the swiftly evolving global health scenario and the rapid realization of the negative effects of unregulated food processing and overmedication, plant-based products have received well-deserved attention (Noreen et al., 2021).The growing interest in foods that can act as medications is a consequence of a greater understanding of the significance of diet and the pursuit of health.'Functional foods' or 'nutraceuticals' are foods or dietary supplements that may provide health benefits beyond simply meeting nutritional requirements.Beyond what would be expected based on their nutritional value, functional foods improve health (Naik et al., 2018;Tufail et al., 2021).Numerous ancient foods with beneficial properties are being discovered, and healthy ingredients are being added to new food products.
Flaxseed is gaining recognition as a functional diet because it is rich in phytochemicals, alphalinoleniclinolenic acid, an essential omega-3 fatty acids fatty acid, and other nutrients (Noreen et al., 2020).In addition to providing energy and dietary fiber (flax precursor), flaxseed was selected as one of six neutraceuticals (Seralthan and Baskaran, 2020;Shaikh et al., 2020) (Figure 1) due to its nutritional value.Due to the high concentration of omega-3 fatty acids, flaxseeds are becoming a popular addition to the vegetarian diets of many health-conscious consumers.Flaxseeds have a bright, smooth, and solid shell.The color of flax varies depending on whether it is of the brown or gold variety, from dark amber to rusty brown.About 15% of the mucilage in the embryo's testa or envelope is mucilage.Flaxseed is a rich source of fat, protein, and dietary fiber as mentioned in Table 1.The composition of flaxseed can vary depending on its genetics, the climate in which it develops, and the processing technique (Rodrigues et MINI REVIEW al., 2012).On average, brown Canadian flaxseed contains 41% fat, 20% protein, 28% total dietary fiber, 7.7% moisture, and 3.4% ash (Viveky et al., 2015;Bhavana et al., 2021)).As the concentration of fatty acids increases, the amino acid content of the seed decreases.The high concentration of unsaturated lipids in flaxseeds is now widely acknowledged (Aly-Aldin et al., 2015).Due to its nutritional composition, which has positive effects on disease prevention by providing health-beneficial elements, linseed has become known as a functional food (Yasmeen et al., 2018).

Compositions
Flaxseeds have a bright, smooth, and solid shell.The color of flax varies depending on whether it is of the brown or gold variety, from dark amber to rusty brown.About 15% of the mucilage in the embryo's testa or envelope is mucilage.Flaxseed is a rich source of fat, protein, and dietary fiber as mentioned in Table 1.The composition of flaxseed can vary depending on its genetics, the climate in which it develops, and the processing technique (Rodrigues et al., 2012).On average, brown Canadian flaxseed contains 41% fat, 20% protein, 28% total dietary fiber, 7.7% moisture, and 3.4% ash (Viveky et al., 2015;Bhavana et al., 2021).As the concentration of fatty acids increases, the amino acid content of the seed decreases.The high concentration of unsaturated lipids in flaxseeds is now widely acknowledged (Aly-Aldin et al., 2015).Due to its nutritional composition, which has positive effects on disease prevention by providing health-beneficial elements, linseed has become known as a functional food (Yasmeen et al., 2018).

Macronutrients in flaxseed
In the past, flaxseed was prized for its high-fat content, which provides a unique combination of fatty acids.Omega-3 fatty acid alpha-linoleniclinolenic acid is prevalent in flaxseed.Several chronic diseases, including type 2 diabetes, kidney failure, rheumatoid arthritis, high blood pressure, coronary heart disease, stroke, Alzheimer's disease, alcoholism, and certain types of cancer, can be prevented or managed with the aid of omega-3 fatty acids (Kim and Chung, 2011).Flaxseed oil contains significant levels of C18:3, n-3 alphalinolenic acid, according to a Canadian Grain Board approximation (Okhti et al., 2016).The lipid content was calculated using the Official Method Am 2-93 of the American Oil Chemists' Society (AOCS).7.7% of the substance was damp.ALA, or alpha-linolenic acid, is an essential omega-3 fatty acid.The observation that omega -3 fatty acids have a cancer-inhibiting effect has led to the theory that flaxseed fatty acid cosmetics may render it tumor-protective (Rodriguez-Leyva et al., 2013).As one of the most nutrient-dense plant proteins, legume protein is believed to have an amino acid composition most similar to flax protein.The quantities of amino acids in the proteins of the two flax cultivars.Flax contains no gluten.Gliadin, which is rich in amino acids such as proline and glutamine, is the gluten component responsible for the onset of "celiac disease" (Wu et al., 2010;Lan et al., 2020).Flaxseed is low in carbohydrates.Therefore, flax contributes a negligible quantity to the total amount of carbohydrates consumed.The chemical formula for carbohydrates is CHO.There are 1 g of total carbohydrates, including glucose and sugars, and 28 g of total dietary fiber per 100 g of flaxseeds (Chaudhary et al., 2018;de la Bastida et al., 2021).

Fiber content in flaxseed
The sum of dietary fiber and physiological fiber yields the total amount of energy.Functional energy is derived from the separation of nondigestible carbohydrates from plants.Since they are not digested and absorbed by the human small intestine (Khouryieh and Aramouni, 2012), functional or dietary fibers migrate into the large intestine relatively quietly.Approximately 28% of the weight of whole flaxseeds is comprised of total fiber.On the basis of solubility, there are primarily two types of fiber: soluble and insoluble.Flax contains both soluble and insoluble dietary fiber as mentioned in Table 2. Dietary fiber functions as a bulking agent in the intestine.It decreases the time required for food to travel through the colon while increasing stool weight and viscosity.In this way, dietary fiber promotes bowel movements, reduces blood lipids, and helps regulate appetite and blood sugar.High-fiber   (Man et al., 2021).

Lignins
It is a densely branched fiber found in the cell walls of woody plants.Lignan is a substance with a similar name to lignins (Suri et al., 2020).Both are associated with cell wall polysaccharides and constitute plant cell walls.Lignins contribute to the cell wall's strength and rigidity.Phytochemicals known as lignans are presently being studied for their potential role in human nutrition, particularly in hormone-related cancer, osteoporosis and cardiovascular diseases.In particular, flaxseeds are the richest dietary source of lignan precursors.When ingested, lignan precursors are converted to enterolignans, enterodiol and enterolactone, by bacteria that normally colonize the human intestine.The principal lignan precursor found in flaxseed is secoisolariciresinol diglucoside (Wu et al., 2010;Prajapati et al., 2016).

Phenolics
Phenolics are plant-derived organic compounds that serve a variety of functions, such as imparting color to plants and attracting bees and other pollinators (Zhang et al., 2019).Multiple phenolic compounds appear to have antioxidant and cancer-fighting properties in humans (de la Bastida et al., 2021).There are at least three different types of phenolics in flax (Amin and Thakur, 2014), including phenolic acids (approximately 1%) flavonoids (35-70 mg/100 g) and lignans in flax.Lignans range from 1 mg/g of seed to over 26 mg/g of seed (Wu et al., 2010).Compared to other plant sources, flax contains 75 to 100 times more lignans.They are also considered phytoestrogens because they help the body regulate its own hormone levels, including estrogen.The most abundant lignan in flaxseed is Secoisolariciresinol Diglucoside (SDG), a component of a linear ester-linked complex in which the C6-OH of the hyperglycemia in SDG is esterified to the carboxylic acid of hydroxymethyl glutaric acid.

Minerals and vitamins
Flaxseed contains numerous water-and fat-soluble vitamins (Dobrowolska and Regulska-Ilow, 2021), as detailed in Table 3. Vitamin E is abundant in flax, predominantly in the form of gamma-tocopherol.Gamma-tocopherol is an antioxidant that reduces the risk of cardiovascular disease, certain cancers, and Alzheimer's disease (Meagher et al., 1999;Khare et al., 2021).In addition, it prevents the oxidation of cell proteins and fats and promotes the excretion of sodium through the urine, which may assist in lowering blood pressure.The concentration of tocopherol in flax is affected by the variety, seed maturity, growing region, environmental variables, and extraction method.Levels of gamma-tocopherol can range from 0.7 to 3.2 mg per tablespoon of ground flax or from 8.5 to 39.5 mg per 100 g of seed (Suri et al., 2020).Vitamin K is identified in plants as phylloquinone, which is present in flax in low concentrations.Vitamin K is essential for the formation of proteins involved in blood coagulation and bone growth (Herchi et al., 2015).A 250 mL (8 oz) bottle of low-fat yogurt with fruit, 30 g (1 oz) of pecan halves, and half of a fried chicken breast (140 g) all contain the same quantity of magnesium per meal as one tablespoon of milled flaxseeds containing 34 mg of magnesium.A hard-boiled egg, a 175 mL (6 oz) mug of brewed tea, and a standard slice of pumpernickel bread all contain nearly the same quantity of oxygen per tablespoon as milled flax (66 mg) (Wu et al., 2010;Dobrowolska and Regulska-Ilow, 2021).Flax has a lower sodium content.Phytic acid and oxalate, which are present in flaxseed, have the ability to form insoluble complexes with calcium, copper, iron, magnesium, and zinc.The study concluded that alpha-, delta-, and gamma-tocotrienol, as well as beta-tocopherol, do not qualify as vitamin E molecules (Ibrahim et al., 2020) (Khalil et al., 2021).In the case of rodents, existing research suggests that phytic acid has the potential to lower blood glucose levels and mitigate the likelihood of developing gastrointestinal cancer (Zhuang et al., 2021).

Benefits of flaxseed
One serving of flaxseed provides a good amount of protein, fiber, and omega-3 fatty acids.It may help lower the risk of some cancers, help maintain a healthy weight, and reduce cholesterol and blood pressure and other health conditions as mentioned in Figure 2 and Table 4.In India, flaxseed has a lengthy history of use, and its medicinal qualities and nutritional value are highly valued (Eliasson et al., 2003;Noreen Tufail et al., 2023a).As flaxseed chutney, flaxseed is consumed to a reduced extent in Southern India.Linum usitatissimum L, the plant that produces linseed, is a member of the Linoceae family.Secoisolariciresinol diglucoside, a precursor to mammalian lignans, is 75-800 times more concentrated in flaxseed than in other plants (Khalil et al., 2021).Initial laboratory investigations on the lipidlowering and liver-protective effects of linseed chutney in rats were promising (Mohamed et al., 2020).It has been shown that whole flaxseeds reduce levels of total and LDL cholesterol, nocturnal glucose absorption, and certain inflammatory markers, and increase blood levels of omega-3 fatty acids.Since defatted flaxseeds have the same cholesterol-lowering effect as whole flaxseeds, the lignans and/or fiber in flaxseeds are responsible for their cholesterol-lowering properties.The two primary nutrients of flax, ALA and SDG, are resistant to roasting temperatures.
According to one study, heating whole or pulverized flax at temperatures as high as 350°C for 60 mins had little effect on the fatty acid content or oxidation and did not result in the formation of new trans forms of ALA or other undesirable fatty acid byproducts.In addition to providing nutritional benefits, the gluten-free protein and fiber content of flaxseed also possesses antioxidant, anticancer, and antibacterial properties (Khalil et al., 2021).Humans can tolerate and derive nutritional benefits from up to 50 g of high-alpha-linolenic-acid flaxseed per day by increasing levels of n-3 fatty acids in plasma and erythrocytes and decreasing postprandial blood glucose responses.After four weeks of daily flaxseed consumption, alpha linolenate and n-3 polyunsaturates were detected in adipose tissue.In Tenda and Toyo (2021) Antiinflammatory Among components of flaxseeds, long-chain ω-3 fatty acids are especially acknowledged for their anti-inflammatory effects.Flaxseed and its derivatives are beneficial for human health, possibly because of their anti-inflammatory effects.Creactive protein (CRP), a sensitive marker of inflammation was chosen to evaluate the anti-inflammatory effects of flaxseed.(Khalil et al., 2021).
According to a comparison of ALA's biological effects with those of long-chain omega-3 derivatives, ALA does not possess the same biological effects as the long-chain omega-3 fatty acids found in marine fish oils.When ALA is metabolized, eicosapentaenoic acid may assume the role of arachidonic acid in membrane phospholipids.Consumption of flaxseed oil may have anti-allergic, antiatherosclerotic, and antiarrhythmic effects.It may also alter the production of eicosanoids, the effectiveness of blood clots, and other membrane-dependent responses.It has been shown that flaxseed oil has beneficial effects on the management and prevention of cardiovascular disease.Significant quantities of 2 cinnamic acid glycoside have also been identified in flaxseed and lignan extracts.According to a number of investigations, the conversion of flaxseed into the mammalian lignans enterolactone (EL) and enterodiol (ED) is responsible for their biological activity (Chen et al., 2022).Flaxseed contains a higher concentration of the plant precursor secoisolariciresinol diglucoside, which is used by microorganisms in the colon to produce mammalian lignans enterolactone and enterodiol (Stewart et al., 2020).
According to studies on the bioavailability of ALA, only milled flaxseed and flax oil significantly increased plasma levels of ALA, while whole flaxseed did not.Several participants experienced negative gastrointestinal effects within four weeks after consuming whole seed and oil preparations.The milled form of flaxseed may be an excellent option for human consumption if you wish to avoid negative side effects while giving your body a substantial ALA boost (Wang and Bao, 2019).In individuals with hyperlipidemia, ground flaxseed reduced Lp (a), increased insulin sensitivity, and had a small but transient effect on LDL-C.The effect of flaxseed on diminishing HDL-C in men.Only a few flaxrelated allergic reactions have been reported in the medical literature, indicating that flax food allergy is relatively uncommon (Noreen et al., 2023b).Plants contain cyanogenic glycosides, a class of chemical compounds that, when broken down by enzymes or organic acids, emit cyanide.In multiple clinical studies, volunteers ingested muffins containing 50 g (5-6 tbsp) of milled flax daily for up to 6 weeks without experiencing adverse effects.The absence of cyanogenic glycosides in ground flax indicates that heating destroys the enzyme responsible for glycoside metabolism (Naik et al., 2018).

Diabetes-combating properties of flaxseed
Daily lignan supplementation improved glycemic control in patients with type 2 diabetes very marginally, but statistically significantly, without affecting fasting glucose levels, lipid profiles, or insulin sensitivity (Özbiçer et al., 2022).Ingestion of flaxseed fiber decreased peak blood glucose levels in type II diabetic patients as mentioned in Figure 3.The poorest of the impoverished who suffer from diabetes in rural areas can use flax cake as a supplement after the oil has been extracted.In Zucker diabetic fatty/Gmi-fa/fa female rats, it has been discovered that flaxseed-extracted SDG delays the advent of diabetes (Tufail et al., 2021).Lignin from flaxseed, SDG improved hyperlipidaemia, hypercholesterolaemia, hyperinsulinemia, and hyperleptinemia; decreased visceral and hepatic fat accumulation resulting from high-fat diets.These effects may reduce the risk of cardiovascular disease associated with lifestyle disorders such as diabetes, atherosclerosis, and hypertension, and help prevent obesity.In addition to containing PUFA and dietary fiber, flaxseeds are a promising food for lowering the risk of lifestyle-related disorders (Kim et al., 2022).

Anti-oxidative actions of flaxseed
The antioxidant activity of flaxseed has been shown to reduce total cholesterol and platelet aggregation (Naik et al., 2018).In the past, it has been demonstrated that the mammalian lignans ED and EL, as well as the flaxseed lignan secoisolariciresinol diglucoside (SDG), are all effective antioxidants against DNA damage and lipid peroxidation.At supraphysiological concentrations, Secoisolariciresinol (SECO) inhibits the chemiluminescence of active cells.Also evaluated were EL and ED.It was believed that the 3-methoxy-4hydroxy substituents of SDG and SECO were responsible for the antioxidant properties of lignan (Aly-Aldin et al., 2015).The flaxseed compound secoisolariciresinol diglucoside has been shown to be effective in deferring or preventing the onset of type-1 and type-2 diabetes.It has been suggested that the antioxidant properties of SDG are responsible for its hypoglycemic effects in type-2 diabetes.phosphoenolpyruvate carboxykinase, a rate-limiting enzyme in the gluconeogenesis pathway, may be responsible for the hypoglycemic effect of SDG in type-  (Tenda and Toyo, 2021).Lower levels of lipid peroxidation (TBARS) and the predictive enzymeglutamyl transpeptidase were evidence of the flaxseed chutney's antioxidant properties in rodents treated with azoxymethane.Antioxidants play an important role in our health as mentioned in Figure 4.

Anti-inflammation properties of flaxseed
After receiving lignan capsules (360 mg/d) for 12 weeks, diabetic participants with mild hypercholesterolemia had substantially reduced Creactive protein levels (Sharma and Saini, 2022).Flaxseed lignans are converted by intestinal microorganisms into the so-called entero lignans enterodiol and enterolactone.Little information is available on the bioavailability of entero-lignans; however, the relative bioavailability of enterolignans in whole flaxseed was 28% greater than that of powdered flaxseed (p<0.05),thereby reducing relative coronary disease risk factors.Models of lupus and polycystic kidney disease have demonstrated the beneficial effects of flaxseed or SDG.It has also been reported that flaxseed has hepatoprotective properties.Mechanistically, the reported bioactivities can be explained in a number of ways, including participation in hormone availability or metabolism, angiogenesis, antioxidation, and gene repression (Ume Salma et al., 2019).

Anti-cancer properties of flaxseed
Although there are some studies with either inconclusive or unfavorable results, the majority of studies on the effects of lignans on breast, colon, prostate, and thyroid cancer have demonstrated favorable outcomes.In animal models, flaxseed has been found to reduce colon and breast cancer incidence and early risk factors (Hanaa et al., 2017).Flaxseed lignans have been shown to reduce mammary tumor size by more than 50% and tumor number by 37% in rats subjected to carcinogens (Ji et al., 2019).Influence of flaxseed consumption on cancer risk indicators Epidemiologic studies have also demonstrated that vegetarian diets reduce the incidence of breast cancer (Barthet et al., 2014) and that lignin concentrations in omnivores and breast cancer patients are significantly lower.Consequently, it is becoming increasingly evident that lignans possess a variety of advantageous properties.Both dietary fiber and phytoestrogen have been found to have anti-cancer properties.The markedly increased lignan excretion in the urine of premenopausal women after consuming flaxseeds (Hussein et al., 2014) suggests that the chemoprotective effects of flaxseed may have been mediated by mechanisms other than a hormonal effect.It has been discovered that flaxseed consumption has significant antiatherogenic effects.The antiatherogenic effect of flaxseeds was demonstrated when 10% flaxseed was added to the diets of LDL receptordeficient (Hussein et al., 2014).This resulted in a reduction of cholesterol levels in the bloodstream.

Nephrological properties of flaxseed
In animal models of renal injury, such as Han: SP RD-cy Polycystic Kidney Disease (PKD), flaxseed derivatives, including oil and flax lignans, modulate the progression of renal injury (Podstawczyk et al., 2015).Male obese SHR/N-cp rats were randomly assigned to one of three diets consisting of 20% casein, 20% soy protein concentrate, or 20% flaxseed meal.Except for the protein source, all three diets had comparable quantities of protein, fat, carbs, minerals, and vitamins.All animals were fed these foods for a period of six months.All three groups exhibited hyperglycemia and hyperinsulinemia during fasting, along with comparable rates of food consumption and weight gain (Park et al., 1999).Although there was no difference in plasma glucose levels between the three groups, the plasma insulin levels of rats fed flaxseed meal were significantly lower than those fed casein or soy protein concentrate.In addition, there were no discernible differences between the three groups in terms of mean plasma creatinine, creatinine clearance, or urine urea excretion.In contrast, rats fed flaxseed excreted significantly less protein in their urine (P<0.01)than rats fed casein or soy protein concentrate.reducing proteinuria and kidney histologic abnormalities in this model.Proteinuria and renal impairment were reduced independently of protein consumption and glycemic management.It is unknown at this time which dietary component(s) of flaxseed meal are responsible for the renal protective effect (Navaie et al., 2018).

Flaxseed for healthy bones
When individuals ingest foods rich in omega-3 fats, the ratio of omega-6 to omega-3 fats in their diet decreases, preventing excessive bone turnover and promoting bone health (de Abreu Maíra et al., 2018).When given 2 tablespoons of crushed flaxseed twice a day for six weeks, women who were experiencing 14 or more hot flashes per week and were not using oestrogen to manage their menopausal symptoms saw a reduction of 50% in their daily hot flashes.In addition, the intensity of the women's hot flushes decreased by 57%.Side effects included abdominal bloating (14 women) and mild diarrhea (8 women) (da Costa et al., 2016).

Conclusion
Functional foods and nutraceuticals may reduce the healthcare system's burden through continuous prevention.Continuous prevention with functional meals and nutraceuticals may lower healthcare costs.Many industrialized and developing nations employ plantbased meals in primary healthcare.Plant-based diets contain phytochemicals and bioactive substances.Functional foods and healthy diets should consider the synergistic effects of a mixture of bioactive in-source materials and complementary phytochemicals from different sources.Nutraceuticals and functional foods increase health and happiness.Thirty years of research have shown flaxseed's nutritional benefits.Processing innovations allow health-conscious consumers to find flaxseed in numerous nutritious forms.Traditional medicine and diet use flaxseed ligans.Flaxseed secoisolariciresinol diglucoside enabled studying SDG and its metabolites' anti-tumor properties easily.Enterolactone and enterodiol inhibit cell proliferation and early breast and colon cancer risk indicators in animals.ALA, fiber, and lignans make flaxseed a promising cardiovascular health food.Flax, the richest source of ALA and soluble fiber, increases blood eicosapentaenoic acid and ALA, lowers total and LDL cholesterol, and reduces postprandial glucose absorption.How this functional diet reduces cancer and cardiovascular risks needs further study.Studying how flaxseed components affect lifestyle diseases and cancer cellular pathways is crucial.

Figure
Figure 2. Health benefits of flaxseed.

Figure 3 .
Figure 3.Effect of flaxseed on the pancreas.

Table 2 .
. The flaxseeds are shown to possess a phytic acid content ranging from Dietary fiber of flaxseed.

Table 3 .
Minerals and vitamins in flaxseed.8% to 1.5%, alongside a minimal oxalate concentration of less than 10 mg per kilogram.Flaxseed, peanuts, and soybeans exhibit comparable levels of phytic acid content.Phytic acid is found in a wide variety of plantbased diets.Insufficient intake of phytate, calcium, and zinc by rats has been observed to result in stunted development and a decrease in zinc levels in their bones Source: Parikh et al. (2021).https://doi.org/10.26656/fr.2017.8(5).310© 2024 The Authors.Published by Rynnye Lyan Resources MINI REVIEW 0.

Table 4 .
Health benefits of flaxseed.