Saturated Fat Controversy On Human Health Essay Example


Over the last decade, there has been and continues to be controversy about what constitutes a healthy diet. Saturated fats are at the center of this controversy as new perspectives challenge their role in causing cardiovascular disease. It’s approximately 41 years since the first dietary guidelines were issued to the American People and saturated fats were categorized as a causative factor in cardiovascular diseases. A few years later, the United Kingdom adopted comparable dietary standards to those in the United States. Overall fat consumption was limited to 30% of total calories, with saturated fat consumption limited to 10% of total calories in successive guidelines editions (Cassiday, 2021). However, new findings and reevaluation of previous research have cast doubt on whether dietary fat is as harmful as specialists have claimed over the past three decades.


Cholesterol in our bodies is often carried by specific proteins called lipoproteins. Basically, lipoproteins are classified based on their densities with two of them being the most significant in causing heart and cardiovascular diseases. These include the high-density lipoprotein (HDL) and the low-density lipoprotein (LDL). On the other hand, coronary arteries are essentially hollow tubes with a very thin endothelium lining. The endothelium lining is constantly in touch with the blood, which transports lipoproteins like LDL. So, essentially the LDL particle does leave the bloodstream, pierce the endothelium, and enter the delicate arterial wall. On the other hand, High-Density Lipoproteins (HDL), and have the reverse effect as they drag cholesterol away from arterial walls, lowering the risk of cardiovascular diseases.

Following the increases evidence suggesting saturated fat and cholesterol don’t necessarily increase cholesterol levels in the blood for the majority of the population. A group of three researchers go further and propose the homeoviscous adaptation to dietary lipids (HADL) model, in an attempt to explain fluctuations in lipoprotein cholesterol as an adaptive homeostatic function that helps to maintain cell membrane fluidity for optimal cell function (University of Bergen, 2021). These scholars argue that when saturated fats replace polyunsaturated fats in the diet, less cholesterol is required to maintain cell membrane fluidity. The reverse is also true as polyunsaturated fats from our diet reach the cell membranes and cause them to become more fluid. In essence, cells incorporate cholesterol from circulation to regulate the fluidity of their membranes. According to the researchers’ methodology, a lot of polyunsaturated fats intake lowers blood cholesterol levels.

These authors argue that body cells modify their membrane fluidity in response to changes in their environment, such as access to different forms of fat in a phenomenon known as Homeoviscous adaptation. This phenomenon has also been seen in bacteria, animals, and human skin cells. This is quite fundamental in human physiology according to these authors.

Since nutrition research is predominantly focused on the interplay between foods, health, and disease, these researchers went a little bit further to understand the causation factors as well as why cholesterol changes occur. This is where the new HADL model, which is based on adaptable human physiology, comes into action arguing that cells need to modify their cholesterol content, and hence blood cholesterol, when dietary fats vary (University of Bergen, 2021).

Zinöcker and colleagues also discuss other causes of high LDL-cholesterol in persons with cardiovascular disease, such as low-grade inflammation and insulin resistance. For them, increased blood cholesterol due to metabolic disturbances must be distinguished from increased blood cholesterol due to a significant shift in dietary saturated fatty acid consumption. It also raises doubts about the value of decreasing blood cholesterol by eating more polyunsaturated fatty acids rather than treating the underlying reason.

The authors argue that the rationale behind the HADL model is that the effect of dietary lipids on blood cholesterol is not a pathogenic reaction, but rather a perfectly normal and even good adaptation to dietary changes.


On the other hand, the homeoviscous adaptation to dietary lipids (HADL) model has received criticism in equal measure. Researchers Christensen et al (2021), argue that the HADL model is wrong as Lipoproteins transfer cholesterol from the bloodstream, and the bulk of it is present in apoB-100-containing LDL particles in humans. These apoB-100 originate from VLDLS and are continuously being secreted by the liver. Moreover, hepatocytes continuously remove LDL particles and thus LDL particles could pile up in the plasma in case of increased VLDL secretion or decreased LDL clearance. This implies that LDL particle components are distributed into various cellular pools after degradation in lysosomes. For example, cholesterol would be deposited as lipid granules, integrated into membranes, used for VLDL particle biosynthesis, or discharged into the bile ducts as bile salts or cholesterol to travel to the gut for reabsorption or eventual excretion.

Christensen et al (2021) also argue that, in variation to glucose homeostasis, no hormonal mechanism has developed to maintain a restricted range of plasma cholesterol concentrations. Since every cell can produce cholesterol, no cell has an absolute necessity for cholesterol absorption (6–8). As a result, plasma LDL-cholesterol concentrations can be very low (but not zero) with few side effects. Contemporary research shows that altered fatty acids trigger some changes in cell membrane lipids and this helps explain LDL-cholesterol changes in intervention studies.

Thirdly, it’s biologically proven that free cholesterol is poisonous and since human cells are unable to break down cholesterol granules, a balance between cholesterol input and outflow via nutrition and biosynthesis, as well as use and excretion occurs. Also, it’s an indisputable fact that all human body cells can produce cholesterol, and as such cellular cholesterol shortage arises only when cholesterol synthesis is faulty. Homozygous and Heterozygous familial hypercholesterolemia patients, for example, have a 50% and 100% reduction in cellular LDL uptake, respectively, but show no symptoms of cholesterol deficiency. On the other hand, cholesterol synthesis deficiency, as evidenced by Smith–Lemli–Opitz syndrome, is, harmful from the beginning of life.


In conclusion, these critics argue that the HADL model authors offered a skewed scientific explanation and ignored data that obviously contradicts their theory. According to these researchers, the HADL hypothesis contradicts existing information, and as a result, their hypothesis is wrong.

Illustrate the impact of food policy and regulation on food provision, food choice, and nutritional health relevant to your chosen nutrient. (1500 words)

Dietary Policy Guidelines

According to Cassiday (2021) the first dietary guidelines were announced in 1980 in the USA after a few clinical trials and some randomized epidemiological research. As a result, these guidelines were based almost entirely on epidemiological research. Some experts argue that it relied heavily on the work of renowned researcher Ancel Keys who had already published the Seven Countries Study that compared the diet and health of middle-aged men in Greece, Italy, Yugoslavia, Finland, Japan, the Netherlands, and the United States. Key’s research had concluded that those men who ate largely fish, grains, nuts, and vegetables lived longer than the group that took dairy or meat usually classified as saturated fats majorly from heart disease. There were other epidemiological studies and controlled clinical trials that yielded mixed results when it came to the role of saturated fat intake and the risk of heart disease. In recent years, individual researchers have produced inconsistent results on the link between dietary saturated fats and heart disease, and thus call for a more research on the link between different types of cholesterol particles in the body and unsaturated fats. However, when individual studies differ, researchers can use also use meta-analysis to combine data from several studies to uncover trends. Some of the notable meta-analysis researches include:

Siri-Tarino et al (2009) published a cohort studies focusing on healthy persons who differed in saturated fat intake. The findings showed that larger consumption of saturated fat was not connected with an increased risk of coronary heart disease, stroke, or cardiovascular disease among the participants.

Another study by Harcombe et al., (2015), found based on randomized controlled trials did not provide sufficient evidence that reducing saturated fat intake reduced heart disease fatalities. These authors, therefore, recommended a review of existing dietary advice as it should not have been adopted.

Moreover, Hooper et al (2015) included 15 randomized controlled trials studying over 59000 participants. The results of the study found no significant effect on reducing saturated fat when dealing with strokes or heart attacks. However, this study denoted that replacing some of it with polyunsaturated fat minimized the risk of cardiovascular diseases by 27%.

De Souza RJ, et al 2015, conducted a systematic observational review looking at the association of heart diseases, saturated fat, type 2 diabetes stroke, and death in 73 studies. The results of the analysis revealed that saturated fat intake wasn’t linked with heart diseases, stroke, or type 2 diabetes. The overall conclusion was that people who consumed more saturated fat were not more prone to these diseases as compared to those who ate less.

Lastly Chowdhury (2014) et al review looked at randomized controlled trials for the link between heart diseases or cardiac death and dietary fatty acids. The study conducted on over 550,000 participants in 49 observational studies found no link between saturated fat and the risk of death or heart disease

Despite the never-ending debate, most countries’ health organizations advise minimizing fat, particularly saturated fat, in the general population. According to UK dietary standards, fat should account for up to 35% of our daily energy (calories), whereas carbs should account for roughly 50%. (It’s worth emphasizing that this is a moderate-fat, moderate-carbohydrate diet, rather than a low-fat, high-carbohydrate diet.

The percentages are even lower when it comes to saturated fat. The United Kingdom advises that it should account for no more than 11% of our total food and beverage calories, whereas the United States and the World Health Organization advise that it should account for no more than 10%. Women should consume 20g per day (equal to 2.5 tablespoons butter or four supermarket sausages) and males should consume 30g per day (similar to 2.5 teaspoons butter or four supermarket sausages) (a quarter-pounder hamburger with cheese, plus four tablespoons of double cream)( Dowden,2021).

According to, nutritionists are concerned about the role saturated fat present in our diet in raising LDL cholesterol levels as discussed at the beginning of this paper. Mono- and polyunsaturated fats, on the other hand, have been found to reduce LDL cholesterol, perhaps the reason why the dietary guidelines in many countries advocate substituting unsaturated fats for saturated fats whenever possible. Saturated fats are believed to elevate HDL cholesterol far higher than other fats, perhaps counteracting the negative effects of LDL cholesterol. Tran’s fats, which are meant to replace saturated fats, elevate LDL cholesterol even higher than saturated fats while reducing HDL levels.

The significance of this is that and LDL particle number and LDL cholesterol levels are frequently concordant (i.e., when one is high, the other is high, and vice versa), which is likely why observational studies have shown a link between LDL cholesterol and heart disease. In these circumstances, high LDL cholesterol was a proxy indication for increased LDL particle number. However, recent studies show that this relationship can also be discordant. That is, if a person’s cholesterol is simply tested, not their particle number, they will be misled into thinking they have a low risk of heart disease. Worse, the people who are most likely to show this pattern are those who are at the worst risk: those who have metabolic syndrome or full-blown type 2 diabetes. According to Kathiresan et al (2006), the more metabolic syndrome components such as hypertension, abdominal obesity, insulin resistance, high triglycerides, and low HDL, the more probable LDL particle number will be raised. On the other end, patients with low LDL particle number (LDL-P) and high LDL cholesterol (LDL-C) do not have a high risk of heart diseases and perhaps this explains why they are often treated with statin drugs or cholesterol-lowering drugs. This is a cause for alarm as several studies have linked low cholesterol to the risk of death especially among women and the elderly.

The Petursson et al (2012) study found that women with cholesterol below 195mg/dl were at a greater risk of dying than women with higher cholesterol levels above the cut-off. Another study by Onder et al (2003), showed that elderly people aged over 70 with total cholesterol levels below 160mg/dl faced doubled risk of mortality than those with cholesterol levels between 160 and 199mg/dl. Definitely, this goes against the current belief on the real course of heart and cardiovascular diseases. Besides, low cholesterol is also associated with several health disorders.

Boscarino et al (2009), argue that men with low total cholesterol were seven times at risk of dying prematurely from unnatural causes such as accidents and suicide than other men in the study. An older study by Morgan, et al found that men with low cholesterol were three times at risk of suffering depression than those with high or normal cholesterol. More recently Seneff et al (2011), associated low cholesterol with Alzheimer’s disease.

It’s critical to highlight that most of these studies were observational thus do not prove low cholesterol was the principal cause of the increased risk of disease or death as observed. However, given that we understand the importance of cholesterol, it’s possible that low cholesterol could contribute to some of these diseases directly

The government’s guidelines have frequently been questioned due to a lack of consistency that consuming saturated fats increases the risk of heart diseases, as well as a better knowledge on the impact of fats on different types of cholesterol particles in the body. Some scholars believe it is time to raise, if not eliminate, the saturated fat limit set forth by UK dietary guidelines. Logically, this would bear significant repercussions, ranging from modifying school meals to readjusting manufacturer goals. The official standards for saturated fat would have to be set and incorporated in various foods across the board. Moreover, some scholars argue that existing saturated fat guidelines are not only unsuccessful in decreasing rates of obesity, cardiovascular disease, and type 2 diabetes but are also harmful to one’s health.

The set dietary guidelines could change soon, though research already shows that solidified dairy products like cheese are often avoided due to their highly saturated fat may contain beneficial saturated fatty acids ideal for healing some diseases.

According to reducing saturated fat intakes, even more, would entail significant dietary adjustments. This is because dairy products, meat, and eggs account for 75% of all dietary saturated fat. Lowering the limit of saturated fat by at least 5% of total calories would require banning the items from the food table. Moreover, eliminating them would also deprive people of essential supplies of minerals, vitamins, proteins, and lipids, in addition to decimating the meat and dairy sectors.


It’s ideal to limit the consumption of saturated fats for people with specific medical illnesses or cholesterol issues. Most of the research findings chosen for this article show that saturated fat has no substantial link to heart disease in the average person. However, substituting unsaturated fat for saturated fat may provide significant health advantages. This isn’t to say that saturated fat is “evil”; but rather, it’s neutral with some unsaturated fats being beneficial.


University of Bergen (2021). New perspectives challenge the idea that saturated fats cause heart disease. Retrieved 18 December 2021, from

Christensen, J. J., Telle-Hansen, V. H., Ulven, S. M., Kovanen, P. T., Jauhiainen, M., Öörni, K., & Holven, K. B. (2021). The homeoviscous adaptation to dietary lipids (HADL) hypothesis is probably incorrect. The American Journal of Clinical Nutrition113(6), 1711-1712.

Kathiresan, S., Otvos, J. D., Sullivan, L. M., Keyes, M. J., Schaefer, E. J., Wilson, P. W., … & Robins, S. J. (2006). Increased small low-density lipoprotein particle number: a prominent feature of the metabolic syndrome in the Framingham Heart Study. Circulation113(1), 20-29.

Davidson, M. H., Ballantyne, C. M., Jacobson, T. A., Bittner, V. A., Braun, L. T., Brown, A. S., … & Dicklin, M. R. (2011). Clinical utility of inflammatory markers and advanced lipoprotein testing: advice from an expert panel of lipid specialists. Journal of clinical lipidology5(5), 338-367.

Petursson, H., Sigurdsson, J. A., Bengtsson, C., Nilsen, T. I., & Getz, L. (2012). Is the use of cholesterol in mortality risk algorithms in clinical guidelines valid? Ten years of prospective data from the Norwegian HUNT 2 study. Journal of evaluation in clinical practice18(1), 159-168.

Onder, G., Landi, F., Volpato, S., Fellin, R., Carbonin, P., Gambassi, G., & Bernabei, R. (2003). Serum cholesterol levels and in-hospital mortality in the elderly. The American journal of medicine115(4), 265-271.

Morgan, R. E., Palinkas, L. A., Barrett-Connor, E. L., & Wingard, D. L. (1993). Plasma cholesterol and depressive symptoms in older men. The Lancet341(8837), 75-79.

Seneff, S., Wainwright, G., & Mascitelli, L. (2011). Nutrition and Alzheimer’s disease: the detrimental role of a high carbohydrate diet. European Journal of Internal Medicine22(2), 134-140.

Dowden, A. (2021). The truth about saturated fat. Retrieved 18 December 2021, from

Boscarino, J. A., Erlich, P. M., & Hoffman, S. N. (2009). Low serum cholesterol and external-cause mortality: potential implications for research and surveillance. Journal of psychiatric research43(9), 848-854.

Hooper L, et al. Reduction in saturated fat intake for cardiovascular disease Trusted Source. Cochrane Database Systematic Review, 2015.

Cassiday, L. (2021). Big fat controversy: changing opinions about saturated fats. Retrieved 18 December 2021, from

School-Based Sex Education Essay Example

Sex education for the young is an important aspect that can help children grow knowing what is right for their bodies and what is not. It is important to explore the concept of sex education as a way of helping the young in society develop knowing their bodies well as well as what they might experience (Bragg, et al., 269). For instance, adolescents and teenagers are most vulnerable to sex issues and there is a need for institutions to educate them on the same (Said 950). It is vital to consider aspects that impact the lives of teenagers and the young including peer pressure and other aspects related to globalization. It is the duty of the educational sector to do the right thing and ensure that children are given the correct advice and guidance to see them develop appropriately (Keogh et al. 432). In essence, the essay focuses on handling a common problem that has existed for long in society. The young should be accorded the right sex education in a bid to help them develop well in various aspects. It is important to raise awareness for children regarding sex education for better growth outcomes (García-Vázquez et al. 122). For instance, an online survey that was conducted in 2017 targeting 1000 young people found out that 28% of those aged between 11-12 years had seen online pornography. Equally, 65% of those aged 15-16 years had watched or seen pornographic content. Such facts should prompt the education sector to provide the right guidance on sexual education in a bid to improve outcomes.

Teenagers and adolescents in society are significantly characterized by rapid growth and development, which exposes them to various dangers that should not be overlooked. The stage is a period of transition and children develop sexually, mentally and emotionally, which is why there is a need for educators to teach them what is necessary for their bodies. Equipping children with the right sexual education can be significantly important towards their emotional, physical and social development. In order to help children develop in the right way, there is a need for the education sector to adopt strategic approaches and ensure that equality is achieved for both girls and boys (Keogh et al. 432). It is vital that educators find out what children already know, correct any misinformation and importantly, give facts that can help them understand the need for sexual healthiness. There are various steps that authorities can do to ensure that institutions have employed effective teaching strategies. For instance, creating and improving digital awareness can be strategic towards informing children in society on the need for sexual healthiness (Goldfarb and Lieberman 15). Policymakers in institutions should be keen to implement policies that can improve vigilance on online platforms, especially on sharing pornographic content. sex education for children proves to be effective towards administering the right practices and understanding regarding emotions, feelings and sexual issues.

Globalization has had a big impact on the way education is delivered and ho people create awareness in society. For instance, teaching about safe sex can be done on online platforms and children or the young can assess the same through the internet (Keogh et al. 432). The failure of institutions to implement strategic procedures or educating children can be detrimental to a child’s sexual development and healthiness. Ineffective education in most institutions has exposed children and teenagers to early pregnancies and STIs that should have been otherwise be avoided if the right guidance was offered (Mandigo 43). For instance, teaching about control measures should be part of the sexual education curriculum. Digital technology should be utilized to ensure that better outcomes have been achieved when teaching about sexual healthiness or children in various institutions. Safe sex is at the core of sex education. Noting that it will be hard for adolescents to abstain in an era where they can easily access alcohol and other drugs and internet-based sex videos and pictures, sex education has emphasized the need for protection. On the same note, it is reported that ignorance is a significant cause of the problems facing adolescents, such as unplanned pregnancies (Mandigo 43). However, with sex education, they can make informed decisions important in keeping them safe.

Most sex education programs discuss the different kinds of contraception, such as condoms, that help prevent sexually transmitted diseases while reducing the risk of unplanned pregnancies. With teen pregnancy now being a significant cause of concern worldwide, something has to be done to help save the future generation. In the same vein, a relationship has been established between teen pregnancy and school-based sex education (Bragg, et al., 269). With greater awareness, the rates have dropped, and this is an encouraging trend that must be upheld. Sex education also plays a significant role in highlighting the issue of consent and its impact on promoting healthy relationships. Teaching about empowerment and how to control one’s body can start early on in life and should not just be reserved for high school students. Sex educators can teach adolescents about consent and its significance (Mandigo 43). Approval in this regard would imply that no one has the right to touch them without permission.

Culture is a significant factor that impacts how societies are handling issues on sexual education in a significant manner. For instance, beliefs in some communities affect the way sex education is treated to a large extent. Some communities believe that some aspects can only be taught by their parents and not teachers (Goldfarb and Lieberman 15). For example, some presume that mothers should teach girls on sexual matters as fathers should be take the responsibility of educating their sons on the same. However, the development of globalization has greatly impacted approaches to teaching sexual education in a significant manner (Said 950). Religion should not form a barrier to effective education practices on sex as it can affect healthiness significantly. Cultural beliefs have always been a factor that determines how children grow in societies regarding sex. It is important to note that most societies in the Western culture have significantly accepted changes that have seen better sex outcomes for children compared to those in conservative countries (García-Vázquez et al. 122). Much should be done in the education sector to ensure that success has been achieved regarding sex education. Showing children the right practices through the education sector would make a huge impact on the lives of teenagers and the young in society.

It is also reported that providing adolescents with information on sexuality is a trend that must be avoided, given that it can lead to sexual promiscuity. This is because adolescence is when young people want to discover themselves and explore (Goldfarb and Lieberman 13). Conflicts have also been reported between sex educators and the communities where sex education is taboo. The bottom line is that sex education broadly violates a person’s morals and beliefs, given that it is perceived as an invasion of privacy (Zulu et al. 4). Several schools fail to teach about abstinence. Instead, primary emphasis is placed on safe sex, which has clashed with family and religious values and beliefs (Mandigo 44). This is because sex is sacred and can only be done, discussed, and practiced after marriage. However, these concerns have been addressed. First and foremost, it must be emphasized that school-based sex education is an entitlement of every adolescent (García-Vázquez et al. 122). This is due to the numerous benefits mentioned above. On the other hand, more than 1.85 billion people between 10 and 24 years globally (Keogh et al. 432). It is a group that must be protected for the sake of posterity. To lead healthy and better lives, adolescents will require knowledge about sexual and reproductive health. Adolescents are faced with a series of health problems such as sexually transmitted infections, unplanned pregnancies, sexual violence, unsafe abortion, and early marriages that could make it harder for them to attain their full potential.

It is important to echo the issue of inequalities that are experienced in various places regarding sex education for the young. For instance, the Equality Act of 2010 stipulates clearly that institutions should work hard to ensure that discrimination is eliminated from the system (Goldfarb and Lieberman 15). The prevalence of sexual abuse and other negative sexual outcomes for children vary from one group to another in most societies. For instance, blacks and other people of color indicate a high prevalence than the majority in most places. Children with special needs education in institutions have a higher chance to be sexually abused in most places. Such practices should be eliminated and equality advanced in a bid to ensure that sexual healthiness is achieved (Namukonda et al. 463). Also, people from socioeconomically deprived groups face difficulties in accessing sexual education in most situations. Equality should be enhanced and discrimination eliminated in a bid to improve outcomes in a significant manner. Cases of sexual violence have increased recently, and many go unreported because the victims do not know their rights (Bragg, et al., 269). Furthermore, though believed to be ordinary among adults, sexual violence is also reported among teenagers. It is a worrying trend that has led to unwanted deaths, with sex education playing a crucial in empowering adolescents to make the right decisions.

An important point to consider is that taking care must ensure that this education is not sexually stimulating. In addition, it should not be a distraction for adolescents (Namukonda et al. 463). Cultural differences and personality issues should also be noted. On the other hand, besides providing adolescents with general information, sex education should be person-centered. Simply put, it must be provided in line with the needs of every adolescent and prevailing situation (García-Vázquez et al. 122). Based on the justice principle, every adolescent and teenager has access to appropriate and adequate information. The person’s continuum of development must be considered when providing education. Moreover, it must suit the age, prevailing family conditions, and cultural setting (Goldfarb and Lieberman 15). Sex education should be the foundation of sexual discipline and must begin by ensuring kids are given gender identity. It must continue throughout their developmental stages, physical and mental, in line with their needs. Considering the age and background of the young people during sex education would be necessary. The right time for sex education on the various aspects of adolescent health, including social, physical, psychological, and sexual health, is different (Namukonda et al. 463). Therefore, every area of teenage health must be taught at the right time while taking note of the underlying cultural beliefs and social factors. Decision-making becomes complex when society and parents oppose sex education (Yeniel and Petri 5). It seems that failure to accord adolescents with proper knowledge might put them in great danger. This is because they can easily access much incorrect information on the internet. To this effect, the level at which adolescents understand sex matters must be the criterion, and society and parents should be educated on such issues (García-Vázquez et al. 122). In general, interventions aimed at improving quality sex education will be necessary for guaranteeing the rights of adolescents, their health, and well-being.

In summary, school-based sex education has a significant role in providing adolescents with the knowledge and skills essential in promoting sexual and reproductive health. They are presented with better opportunities to understand sex, deal with relationships, and have the information required to make the right decisions about their health. However, sex education is not widely accepted as some consider adolescent sex debates immoral and uncalled for, emphasizing sex after marriage. In other words, matters of sex should only be discussed and practiced by adults. For school-based sex education to be successful, the moral and ethical concerns that have been raised should be addressed in the curriculum content to ensure that it is accommodative. The only problem is that it will not be easy to prevent this generation from sexual practices given the early exposure; thus, sex education must be motivated by the need to promote the sexual health of adolescents and their well-being while ensuring that they become healthy from now on. In a nutshell, focusing on the whole aspect of sexual health, presented in various grades and bolstered by a perfect environment, will help enhance adolescents’ sexual, emotional, psychological, and social health.

Works Cited

Bragg, Sara, et al. “Dilemmas of school-based relationships and sexuality education for and about consent.” Sex Education 21.3 (2021): 269-283.

García-Vázquez, J., Quintó, L. and Agulló-Tomás, E., 2020. Impact of a sex education programme in terms of knowledge, attitudes and sexual behaviour among adolescents in Asturias (Spain). Global health promotion27(3), pp.122-130.

Goldfarb, Eva S., and Lisa D. Lieberman. “Three decades of research: The case for comprehensive sex education.” Journal of Adolescent Health 68.1 (2021): 13-27.

Keogh, Sarah C., et al. “Classroom implementation of national sexuality education curricula in four low-and middle-income countries.” Sex Education 21.4 (2021): 432-449.

Mandigo, David. “Pros and Cons of Sex Education in School Children: Review.” IDOSR JOURNAL OF APPLIED SCIENCES 5(1) 42-45, 2020

Namukonda, Edith S., et al. “Sexual and reproductive health knowledge, attitudes and service uptake barriers among Zambian in-school adolescents: a mixed methods study.” Sex Education 21.4 (2021): 463-479.

Said, Samira. “Research Spotlight on Single-Sex Education and the Challenging Entailments.” International Journal of Humanities and Cultural Studies (IJHCS) ISSN 2356-5926 2.4 (2016): 950-961.

Yeniel, A. O., and E. Petri. “Pregnancy, childbirth, and sexual function: perceptions and facts.” International urogynecology journal 25.1 (2014): 5-14.

Zulu, Joseph Mumba, et al. “Why teach sexuality education in school? Teacher discretion in implementing comprehensive sexuality education in rural Zambia.” International journal for equity in health 18.1 (2019): 1-10.

Singer And Nicholson Model Of Biological Membranes Sample Paper


For many centuries, the biological composition of cell membrane structure remained one of the biggest scientific paradoxes that attracted considerable attention from biologists. In definition, a membrane refers to the outer cellular boundary of a living cell that appeared over 2.7 billion years, first as a prokaryotic cell, and then as a eukaryotic cell resulting from the evolution process (Lents and Hesterman). Subsequently, the new cell form is thus more complex, characterized by multicellular features. It has highly compartmentalized membrane-bound organelles that primarily regulate the intra-molecular movement between them and protect them from cytoplasm reactions. As aforementioned, scientists have devoted considerable attention to the study of cell membrane structure with the view of understanding their composition and functionality. To this end, Singer and Nicholson in 1972 formulated a model that proposed a descriptive analysis of the cell structure that included its semi-permeability and the two-dimensional liquid composition. In retrospect, the scientists suggested that these characteristics allowed free movement of the lipids and protein components, a position that remains plausible to date. The subsequent discussion of this paper will focus on the cell membrane structure proposed in the Singer and Nicholson model and similar scientific research hypotheses on the cellular biology of the cell membranes towards building an understanding of their composition and functionality spectrums.

Singer and Nicholson model started their experiment from the pre-existing evidence that supported their predisposition to cell membranes’ fluidity characteristics. One of the core research work that helped construct the framework of their model was Frye and Eddin’s research findings that proved the membranes’ fluidity theory using a cell-infusion of a human and mouse cells (Lents and Hesterman). In the experiment, the biologist had labeled the cell membranes of both the mouse and human cell with rhodamine and fluorescent dyes, respectively, and observed the migration process between the two cells proving the fluidity. The figure below illustrates the experiment’s finding that greatly helped to inform the fluid-mosaic model’s theoretical perspectives proposed by Singer and Nicholson.

Hybrid Cell Experiment

Figure 1 Hybrid Cell Experiment

Singer and Nicholson (1972) articulated that the membrane structure was formed as a bi-layer composed of two lipid molecules layers with protein molecules embedded in the middle. In their explanation, the structural fo9rmation of the multilayered cell membrane was similar to a pool of mosaic tiles of both lipids and proteins that freely moved within the cell through the diffusion process. The scientists asserted, “The lipid molecules are like the ocean water, and the proteins are bobbing around like “icebergs…floating in a sea of lipid” (Lents and Hesterman). The scientists used a pictorial representation of the movement to illustrate the cellular membrane structure, as shown in figure 2 below.

Cell membrane proteins float in a sea of phospholipids

Figure 2 Cell membrane proteins float in a sea of phospholipids

To show how the two cells related, they described lipid cells and the proteins using an example of an ocean of lipids molecules where the proteins cells float like icebergs. Using the example, Singer & Nicolson (1972) helped show how the cell membrane’s structural composition of lipid molecules and protein molecules allows the free movement of certain elements that help to plasma reactions in the cells. Thus, following the two biologists’ propositions, the scientific understanding of the composition of cells became clearly defined. By far, since the predispositions made in 1972, the cell membrane structure’s biological composition became understood and helped to form the foundations of future research on the topic (Lents and Hesterman). In more precise terms, the cell membranes’ amphipathic nature composed of a two-lipid layer and a single protein layer became well-defined. More importantly, discovering the special compositional characteristic of the lipids that features phosphate charge allows water solubility of the phospholipid molecules. In retrospect, this special characteristic allows them to allow the diffusion of water-soluble elements such as proteins and lipids, which explains the amphipathic structure of the cell membranes. Singer and Nicholson (1972) illustrated the phospholipid molecules’ concept, as the figure below shows.

Amphipathic Structure of Phospholipids

Figure 3 Amphipathic Structure of Phospholipids

Thus, as the discussions mentioned above indicate, Singer and Nicholson build on the biological composition of the cell membranes in principle on the foundations of the cells’ multi-layer structure. In retrospect, they build the Fluidity-mosaic model by expounding on the structural composition of the cells’ plasma membranes (Lents and Hesterman). The scientists also identified the unique composition of the different types of lipid cells to explain the various ways that the cells overcome barriers of permeability of different elements that are both water-soluble and water-insoluble. In brief, the hydrophilic heads and hydrophobic tails described by Singer and Nicholson (1972) helped to validate the theoretical perspectives therein of how the cell membranes function and allow the free movement of proteins and lipids across the cells.

To conclude, the cell membranes structure, as Singer and Nicholson described helped explain the intracellular biological movements. As Lents and Hesterman avows, “We now understand that the plasma membrane is a very dynamic part of the cell and that is much more than just a barrier”. They are not just passive barriers but rather are very dynamic structures that regulate entry and exit of particular elements based on the findings of multiple experiments that led to the development of the fluid-mosaic model of the cellular model that described the compositional components of the membrane structure and their functionality paradigm.

Works Cited

Lents, N., and D. Hesterman. “Membranes I | Biology | Visionlearning.” Visionlearning, 19 May 2014,